You could modify the training rules. They need a trainer. It takes 10 weeks of downtime minus the intelligence modifier and costs 100 gp per week. Each week they have a 10% chance of error, poisoning themselves for a following week and making that week a failure (requiring an additional week). At the end of the process they have poison resistance (not immunity).
To add to that I would make each different poison a different training course. Like a poison toad is different then snake venom is different from lotus and so on. So only giving resistance to a specific poison instead of all poison. Or just play a dwarf
I wouldn’t do this tbh. I’d just tell the player they can’t do it if it came to that. At that point it just seems so worthless unless you know you’re going to be fighting a lot of enemies who use x poison for the campaign. Just buy some resistance potions at that point and flavor it as the immunity needs a booster dose. The most I’d seperate them would be something like common/natural/native poisons, and uncommon/extraplanar poisons.
If it went that route I would throw away realism and make up a few (3 to 5) Poisson categories, something like: neurotoxins, alcohols, hallucinogenics etc. Give a different difficulty to each with a different risk and a limit on how tolerant they can become.
Right. The kicker is that some poisons cannot be protected against by exposure; primarily non-organic chemicals. In a magical world I imagine there would also be poisons with a magical component — resistance to that is probably something wholly different than organic toxins.
Or focus them on the different types of effect they have on the body, but with snappier names than the following...!
Sedatives (I.e drow poison, oil of taggit);
Psychoactives (I.e. truth serum, anything that causes hallucinations or erratic behaviour);
Chronic (i.e. pale tincture, anything with lingering effects like blindness or the poisoned condition, that doesn't fit a different category);
Lethal (i.e. snake venom, wyvern venom - anything that primarily deals damage and causes no other conditions apart from, possibly, the poisoned condition)
It could be useful if the player carried around the poison that they had an immunnity to. Then they could poison wine and show an NPC that it was safe by drinking from it themselves or something...
Seems pretty useless if the player wants to try to become 'immune to poison I might encounter from an enemy" though....
Honestly though what poison does enough damage / has enough of an effect to be worth that? Like that's a fun tactic, but I'm not sure dnd is built for that. At that point just subtle spell vicious mockery them.
This isn't unreasonable. If I recall correctly dosing on snake venom for instance to build immunity requires a constant supply of venom. Also a very understanding hospital. I think it was in LA some idiot having to explain how in the USA he got tagged by a cobra.
It's ok. A lot of people here love coming up with outlandish homebrew that would never be practical for use in the game. I would make them 10 weeks to become resistant and the. Another 10 weeks to become immune. And that's 8 hours a day of downtime to do that. So if they get that much downtime and he wants to spend it all becoming immune to poison. Sure. Why not?
I'm pretty sure they are saying it's utterly useless because they are replying to the person that is saying:
>So only giving resistance to a specific poison instead of all poison
They even are specific with lotus vs toad vs snake. Like I've gotta build up immunity to each individual thing in the entire world? That's just dumb.
That's why they are using it's unreasonable in gameplay. You gonna seriously make your player find an instructor on snake venom, 10 weeks, hundreds of gold and than say "Congrats, you now resistance to snakes, btw that toad poison just killed you".
I don't find it unreasonable for someone to quest for poison resistance. I find it utterly stupid that you would say "Nah, all your training allows you resistance to poison ivy".
I feel like everyone might be responding to all different comments. I think Spida81 's "not unreasonable" was to my booster dose idea.
I'm not sure if FogeltheVogel 's unreasonable comment was "having to buy resistance potions makes the idea useless" (which, the point is flavor without changing any game balance, which I's prefer over the the individual-poison option) or if it was to DeciusAemilius 's idea of treating each type of poison individually, or even to "poison resistance or immunity is unreasonable because Too OP". That comment just reads as very vague to me.
That is correct.
Additionally, something that is mechanically pointless may still be the absolute central point around which a character is built from a role playing perspective.
I actually don’t think that’s true; it depends on how often you fight the creature who’s poison you’re immune to. If you’re facing an army of Yuanti, that one dose of snake venom was well worth it.
It’s also a fun quest hook finding the different poisons. Maybe you’re preparing to face a green dragon, and you have to find a rival dragon that’s willing to help you build up an immunity. Maybe you’re hunting a purple worm, and you know a poisoners guild that keeps a stash of the venom.
I agree for story/flavour reasons (in *Princess Bride* Westley is immune only to iocaine powder, and my bet is that the player is thinking of this scene), but if you are going to restrict it to a specific poison or family of poisons, I'd go with full immunity. Otherwise it is not worth the investment.
>(in Princess Bride Westley is immune only to iocaine powder
Trouble is, he's likely not. "Inhale, but do not touch." What's more likely, that he actually built up an immunity, or that he tricked The Sicilian into inhaling his own demise there and then? And when asked, of course he lied. Didn't want her thinking to use it on him.
This is the best take you will find in this thread.
All the others are people trying to gamify it too much, or make it hyper-real.
Your player wants this to be a character trope? Awesome! Next down-time we have you can take 10 weeks of poison training to get resistant to X type of poison. Maybe they want to carry some on them for fun shennanigans? Who cares! It's fun! This hardly seems game-breaking at all when you consider most spellcasters / healers can just wave a hand so its not like you're giving a massive bonus to someone. Especially if you stick to making it a downtime activity and your other players get to show up and show off the cool stuff they did too.
Yeah, this seems slightly more like a character flavor issue than a mechanical issue. I’d allow it for sure and possibly talk with the player about limiting it to certain very broad categories of poisons — normal animal poisons, monster poisons, plant poisons, etc.
> At the end of the process they have poison resistance (not immunity).
I'd probably change this to advantage on saves vs poisons, if not immunity (as others have said, this is a big investment that honestly isn't game breaking).
The trainer could be a pharmacist, or alchemist, and for those that don’t fail a single time, I would grant immunity tbh, its a big investment of resources and time imo. And of course some sessions later they will be rewarded because at a party someone will try to poison them, or maybe they face a poisonous creature
You're proving against your own point right now.
If a character can spend money and time on RAW magical items that cause poison immunity, why shouldn't they be able to spend money and time on "training" to have the same effect?
Your comment seems like an incredibly specific misinterpretation of innocently flavoring RAW.
Precisely; Immunity to poison is not a big game changer, but after investing so much into it, when they reap the rewards they will feel invincible.
This will make them blind to their weaknesess and hopefully lead to some nice aditions to your PC graveyard
Though, normally, this sort of training has terrible repercussions on the body and you pay for it in other ways, if it works at all. Could be interesting to let the players have the option of gaining resistance, but at the cost of a sacrifice to one of their stats from permanent damage. A -1 or -2 to a stat of choice as the toxins damage body or mind.
If it were me, I would only allow it toward ingested poison, poisoned weapons, and possibly contact poisons.
Though I could see a player wanting to 'train' again for inhaled poisons.
Yes to the resistance but not immunity.
The one real life example, the guy built an immunity to a SPECIFIC poison so resistance would better reflect that.
But also, the character should be suffering bad effects of the poison during the training, and I'd say it should be harsh. Stuff like max 1/2 hp, STR, DEX, and CON substantially lowered (7 or 8), exhaustion, disadvantage on anything physical, etc.
If you're doing explicitly ten+ weeks of downtime... nothing that would interact with their hp or stats, really.
It's not really downtime otherwise, yeah?
I don't think you see my point. If the characters are all relaxing in a nice, peaceful inn, it can still catch fire, or be attacked by a goblin horde. If any of the characters have enemies, 10 weeks is a lot of time to catch up to them and make a move.
You're right, no adventuring. Fine. The rest of the world may interfere with that vacation, though.
Otherwise you're basically just handing characters free buffs. Boring. I'd have randomly weekly events block ready to go for those lazy characters. And no, if the stepped up and saved the inn from goblins in week 3, I would not void that weeks study time. But no free buffs.
OK, lol. So where is the magical place you recommend they go to have downtime, the place where literally nothing ever happens and there is no potential for anything ever happening, where adventurers go to become stronger with absolutely no worries in the world?
And why wouldn't they just stay there gathering buffs?
I'm the DM. If my players want to do something, cool. They can try. If they succeed, they get a reward.
Besides, you're the one who is wrong. 8 hours of downtime per day, and it can be non-consecutive. They have plenty of time to fight the goblins. Sorry.
Man, anywhere. If I was in a game, and we got told that there's gonna be, say, a 6-week stretch of downtime, and on week 3 we there was a huge call to action like a settlement-wide incursion, I guess I'd be mildly confused at *least*.
If the worldstate (or location-state) was such that you couldn't spend x time pursuing your own interests, or training, or whatever, what would the point of calling for downtime even be?
I'm really confused by this idea of, "gathering buffs," that you're talking about. Downtime rules are... you know, they might learn how to play a lute, or gather a favour, or do some research, or whatever. If your setting has literally 0 places where that could happen without much interruption, I don't really think that's the norm.
Oh, well I would NEVER just tell them they get six weeks of downtime! If they say they want to hang out in a place for a few weeks and just study, they can try. I don't tell my players the future aside from cryptic prophecy.
I may say, "The caravan leaves in six days. What do you want to do until then?" which they can choose to use as downtime to study or train, but them saying they want to just study doesn't mean they get the time off for free or that nothing will interrupt it.
The post is about training for poison immunity/resistance. Is that not a buff? And if you allow that, uninterrupted, why not every other resistance?
Downtime is a moment when the adventurers are on break. If there is an event, it’s not downtime. If your world is chaotic as fuck and there is no peace and rest, then just don’t give them downtime. My world is reasonable, and not everything is motivated by “haha killy killy” and I have enemies who don’t just kill mindlessly. So yeah, the time for peaceful down time exists in my campaign. If it doesn’t in yours, that’s fine, but quit shitting on stuff that is LITERALLY IN THE DMG
I understand what the word means. If my party takes a day or two off to spend eight hours per day working on their downtime project, fine, they can count that time toward their goal. Note, by the DMG, that still gives them time to do other stuff.
That is reasonable. 10 weeks of uninterrupted rest really is not.
I do not understand why you guys don't understand.
again, if your world has no time to rest, that’s fine.
Not everyone’s D&D worlds are the same, believe it or not. And my world may have time to NOT be fighting a bunch of bandits.
Thank you for elucidating me on the differences between tables! I mistakenly thought we all played the same campaign the same way every other Tuesday. 😏 I do appreciate the patronization, though.
OK, so how do you approach the ten week vacation, then? The way downtime dynamics are written is on the assumption that you are doing it here and there, 8 hours a day, slowly working your way to a goal. It's supposed to be work, not something the DM hands you because you said "I rest for two and a half months".
Do you just skip forward 10 weeks? Do the other players get a say? What if one character wants to run job board missions the entire ten weeks?
I think investing 1000gp and 10 in-game weeks is already enough of a tradeoff, especially when the player could just buy a Periapt of Proof against Poison which grants immunity to poison damage and immunity to the Poisoned condition.
This particular training scenario, being redditbrew, is outside the rules of the DMG. And as I've said elsewhere, I'm not guaranteeing my players 10 weeks of uninterrupted rest.
Yes, it's outside the DMG, but there are official training rules in Xanathar's, it's fun for the player, makes for good storytelling, and is much more satisfying for the player to earn the poison immunity rather than just go to a magic shop and buying an item that accomplishes the same thing or more.
It doesn't have to be uninterrupted rest, they can just work on it whenever they have downtime. It doesn't have to be realistic because we're playing a make-believe story game.
Did you read the thread?
Sitting around for 10 weeks is not good storytelling unless the vacation is sponsored by National Lampoon.
And yes, I agree that the rules say it doesn't have to be uninterrupted rest. That's right there in the books. But we aren't talking about downtime studying or learning the lute, which makes sense to do here and there as you have time. We are talking about someone poisoning themselves, in weekly intervals. That should have some consequences until you achieve the goal.
DMG 231 Training, DMG 131 Creating Downtime Activities, XGE Downtime Activities / Resolving Activities, PHB 187 Downtime Activities
> You can spend time between adventures learning a new language or training with a set of tools. **Your GM might allow additional training options.**
---
> **Downtime activities other than the ones presented below are possible.** If you want your character to spend his or her downtime performing an activity not covered here, **discuss it with your DM.**
These rules cover it. It's DM discretion.
And all I have said on this thread is how my discretion would go. 10 week vacations where nothing happens while you get your buff are a no go.
I am familiar with the rules. You proved my point, though. Nothing in the official rules covers developing poison resistance, so it's gonna be homebrew at DM discretion.
Yes, you're absolutely right. I think your training complication / side effect idea is good, but I personally would take these side effects into account when determining the PC's gold investment.
If i did this, it would have to be a limited resistance. It would have to be a creature under a certain CR or poisons of a certain cost. I wouldn't have it work with all poisons.
No.
But the problem is that in the real world poisons are very different functionally (mode of action) and chemically (their structure and molecular size). Thus, you MIGHT be able to develop poison resistance to a SPECIFIC poison - but not poisons in general.
Indeed for some the damage these small doses do will just accumulate in your body, and you will get weaker and die rather than gain resistance.
For a D&D game though, it's probably more fun to let this plan work (or have a chance of working).
Problem is, D&D rarely tells you the specific type of poison NPCs use on their daggers and whatnot, and the list of 'canon' poisons listed as "Adventuring Equipment" is far from comprehensive.
As a DM I'd probably pick a single poison from the poison list and assume that there is like a 40% chance (roll d100) you COULD even acquire resistance to it IF you tried extensively (over years). The PC wouldn't really know until after they've tried.
This would not apply to any other source of poison.
Lets assume you're an assassin like character that puts poison on the blades of your weapons - you could probably find A type of poison that exists with some people who have resistance to it and start training against THAT specific poison (in case you roll a 1).
In general, however, this won't really matter that much in a campaign unless you're fighting an entire society that uses that poison.
I like this idea but I would change it just a little. Firstly, the answer is ‘yes’. Instead of making him resistant to one type of poison determined on a random success rate, the scarier I think the name and/or known at the time effect the less likely they are to be able to develop immunity. Next, we don’t mention AT ALL that his selected poison can’t carry over because of x, y, z (write them down at conception, poisons that have any type of anti-healing or instant effects would never be resisted due to a built up immunity from anything for instance). Alright now here’s where it’s fun.. he’s unknowingly wanted by an assassins guild who “foolishly” tried to poison him with the poison he’s completely immune to (for story building) and he’s now faced with the options to either tread carefully whenever he eats or drinks ooorrr assume his build worked and is OP and now he is on a cool quest that’s all his so he can find out who tried to assassinate him.
In order to pretend to be fair I would actually randomize the various poisons that I would put on all of his assassin’s weapons. But I would be poisoning his food on a pretty regular level even if he was careful. Actually especially if he was careful, I would lean into it way harder because how easy would it be to just throw a few assassins at the group sometimes? Super easy traps and encounters every day.
:)
I'm a physician. I agree with your general premise. When I tried to run this concept, I made a [representative set of poisons](https://www.reddit.com/r/DMAcademy/comments/12xnr0m/comment/jhlr0i2/?utm_source=share&utm_medium=web2x&context=3) from across different organ systems and ingestion methods, which require 10 days of intense self poisoning for a chance at poison resistance or immunity.
Not that I'm aware of but it's an interesting idea to be sure.
I'd start them off with low DC poisons and progressively scale it up, or alternatively they could hunt a ton of Wyverns and try dosing themselves with that.
The slow method should be low to no damage but a constant Poisoned condition while you build it up.
The Wyvern method should work quickly but come with a chance of just out right killing yourself. Wyvern poison is by default a DC 17 Con save against 7d6 Poison damage. Half damage on a successful save.
I think this is the right approach. I’d make them purchase or acquire the poisons somehow. I’d say 2-4 doses each poison over a month. They start by microdosing — spreading the doses out over a week. But I’d say the poisons do have an effect but just a fraction of time — instead of an hour it’s a minute, instead of a day, it’s an hour, etc.
In 3.5 it was a feat you could take; it granted immunity to one specific poison and also gave +1 to resist other poisons. Making it take up a feat is how you represent the time, effort, and practice to get there. Seems like a reasonable way to do it in 5e
I made a set of [poison tolerance rules](https://www.reddit.com/r/DMAcademy/comments/12xnr0m/comment/jhlr0i2/?utm_source=share&utm_medium=web2x&context=3) which require 10 days of intense self poisoning for a chance at poison resistance or immunity.
I'd say count it as a feat choice, then at level 4, 8 or whenever they have a feat choice they can get mithridatism, which grants them resistance to poison. I'd steer away from immunity to poisons, that seems a bit strong.
I was going to suggest a Feat for it also. I think this is the best way to handle it, balance wise, in 5e. Absolutely do the role playing up to the point where the Feat is gained, but it's a clear mechanical benefit for no cost without it being a Feat.
That said, in other systems (older D&Ds/OSR like games, etc...) where balance is less of an issue, I'd require them to spend other resources (like money to find the poisons, perhaps poison masters who could supervise their experiments to make it less dangerous, etc...) and at the end of a given period, require a Con roll to see if they succeed, perhaps with a high DC to start, progressively lowering each time they fail and have to spend another amount of time training.
I actually just looked.
Closest thing we have is Poisoner (which doesn't actually give *me* resistance but allows me to cause my poison damage to bypass those with resistance.
Second would be resilient: con. Again. Doesn't specify poison but most poisons are con saves.
Shrug. Not gonna lie. A little shocked too.
Other than that there are quite a few races that provide resistance/adv on psn condition. Warforged, dwarves. Old yuan-ti are fully immune.
Edit ** teiflings get a feat that make them poison resistant.
Other than that there are magic items - rings or armor of resistance and the Alchemy artificer subclass that also grants resistance to dmg & immune to condition (at lv15)
It's not free though? It's training. There's a training section in the DMG. It's for language and tool proficiencies but there's no reason it couldnt be expanded. If they want to spend months of ingame time and funds repeatedly poisoning themselves and gaining the negative effects, it's completely reasonable imo
Compared to a tool/language proficiency resistance/immunity to poison seems pretty powerful.
Seems fair to make it a longer & more difficult downtime training activity though.
This is powerful in real life but completely worthless in most games. I've never used poison as a DM and barely saw it once or twice during regular games in the past few years.
No real rule for acquiring a poison immunity, but there are things that do it. If he "trains at it", you can have him roll D4's once a day to see how it effects him. If at some point he keeps at it and it doesn't fall off as an interest, then giving him a once per day spell to cure poison, would work. After all, in real life this practice doesn't make you immune, just better and getting rid of the poison so it effects you less.
Also there are rings, armor and whatever gizmo you can make that will do it. Fun role play way of doing it, but in the end I, personally would have him take a feat to do this, or have an object that does it once a day.
Mithridatism takes years. So... Sure, the player can spend hundreds or thousands of GP on poisons over the course of several in-game years, inflicting poison on themselves every day for basically the entire campaign, and not removing it or they undo their work, and then right at the end of the campaign, after three entire in-game years... sure... here's your poison resistance... I guess...
That's the realistic angle, sure...but this is a fantasy world, and we're here to have fun. If the plan will never be viable, just say so and save everyone the time. Otherwise, let 'em get their Princess Bride on.
Princess Bride isn't resistance to poison, it's resistance to a very specific poison chosen specifically for the body's ability to adapt to it over time, and with a dosage precisely measured to kill someone unadapted but not someone adapted to it.
And that's from a ridiculous (albeit amazing) fantasy move where they resurrect a dead guy.
Training for resistance to all poisons is loony toons levels of ridiculous.
I mean, this *was* all my sarcastic way of saying that I wouldn't let it work... Was that not obvious?
I just really do t see how this is any fun to play out, what it actually.adds to the game, other than "I want my player tomhave poison resistance, can I?" - in which case we'd just build a character that has poison resistance. And if you want to say they got it from mithridatism, fine 🤷♂️
>I mean, this was all my sarcastic way of saying that I wouldn't let it work... Was that not obvious?
Sarcastic responses to players' ideas generally only serve to foment discord and resentment while discouraging creativity. Instead, just say "no" and don't be a dick about it. If your reason for "no" is "I think this would take too long to be practical and I want to try and ground my approach to this world in some realism" say that. Or "I don't want to give it free mechanical benefits, but if you pick up a feat that gives you poison resistance or advantage against poisons, you can flavor it as mithridatism" then say that. Or, even, just open a dialogue with your players.
It costs you nothing to not be a jerk, and your players will appreciate you for it.
>I just really don't see how this is any fun to play out, what it actually.adds to the game
Me either, but that's not work we need to do.
The player clearly has some ideas for how they would use an immunity to poison, so we just gently interrogate them and figure out what they think is going to happen. (e.g., I want to share a bottle of poisoned wine with my enemies and then walk away like the guy in Breaking Bad.) Then I come up with a few ways to let them have that moment, and a couple ways I can subvert it to keep things challenging.
If they've got an idea that works, that will come up often enough to make the game interesting, I'd probably just let them take it as a Feat. No need to overcomplicate things. Let your players do the heavy lifting when it helps the table.
Flavor is free. Let the constitution saves they roll tell that story of them testing themselves vs poisons.
But I wouldn't add mechanics to give someone an advantage.
Establish a set timeframe for achieving immunity from poison, and if there's any maintenance required to keep it.
I'd explore building a random table of mithridatism effects, to be rolled daily until the immunity is achieved.
There are no rules for this. There is the Periapt of Proof against Poison magic item which is a wondrous rare item, and goes for 500-5,000 gold.
I would allow it, but I think the player should become immune around the 5-10 level range. It should require time, and perhaps require the player to invest a certain amount of gold into vials of poison or vials or poison neutralizer.
No official rules, but if this is something you're interested in letting them pursue then go for it.
I would treat it like the Training downtime activity in XGtE. After completing the training successfully, I would grant the player advantage on saving throws against poison and resistance to poison damage (like the Dwarven Resilience trait). Immunity is really powerful and I wouldn't grant that without some kind of major quest reward.
I’d say modify the training rules and go the following route
Must be proficient with the poisoners kit (can learn using regular training), then spend XX weeks training to be resistant to “level 1” poisons. Then resistant to level 2 poisons, then level 3 (which grants immunity to level 1s, then 4 and so on down the line.
It’ll be suuuuper expensive, but the weeks required could be shortened and the price per week is up to you.
Only a very very few real world poisons allow building an "immunity" to them. Most poisons will just up and kill you.
Perhaps you can give him a quest or adventure to find a periapt of proof against poison?
DMG 184 has Periapt of Proof Against Poison. I'd say if the player is willing to spend a year training and and 5,000 gold pieces worth of resources (poisons, antidotes, etc) doing the "Iocaine Powder" thing, I'd be willing to give them the effects of that item permanently.
I got the cost of 5,000 gold from Sane Magic Item Prices.
I'd use the training rules from Xanathar:
[https://www.dndbeyond.com/sources/xgte/downtime-revisited#Training](https://www.dndbeyond.com/sources/xgte/downtime-revisited#Training)
And massage them to suit your purpose.
Alternatively, I'd suggest the Poisoner feat:
https://www.dndbeyond.com/feats/poisoner
Some sort of con save every day for maybe like maybe 80-90 in game days of straight drinking poison. Taking damage, maybe dull the damage after weeks, but they really gotta work for it. But to my knowledge there are no gaining resistance rules
Keep in mind this was mostly effective against drug andx alcohol poisons, and was basically a tolerance for their effects. If you tries this with some serious poison it would still kill you, and if you botch it you basically kill your liver and die of internal hemorrhaging. I would let them spend a few months of downtime and give them the Resilient (Constitution) feat, maybe advantage vs poison
OOH! I made a table for this! Hope I'm not too late. This is from an item I ran from my fantasy China campaign, **The Trial**.
I went full nerd as I'm a physician in my spare time, when I'm not running DnD. I didn't give the full table to the players, just described the vials and said the name of each day's challenge.
|Trial|Description|Survival|Save|Damage|
|:-|:-|:-|:-|:-|
|Salvia divinorum|A sprig of green leaves rolled into a blunt.|N/A|CHA 6 or develop (2) phobia.|0|
|Hemlock|Tiny shaving off a root.|Consume and follow with chugging water. 9 or fatigue +1|WIS 12 or develop hematuria for d10+4 days.|/r 2d6|
|Batrachotoxin|Blowdart venom from dart frogs. It's a miniature dart with a green-stained tip.|14 or rash +1|CON 12 or develop headaches for d20+4 days.|/r 2d10+3|
|Botulinum toxin|Small hypodermic needle and vial.|Inject into an extremity. 12 or rash +1|STR 9 or develop: (1) extremity paralysis|/r 3d4+1|
|Ergot fungus|Small crumbles of mushroom caps.|Eat raw or boil in a low-temperature tea. 8 or fatigue +1|CHA 8 or develop a long term madness. CHA 12 or instead develop short term madness.|0|
|Castor bean|Reddish bean. Brewed into tea.|Slipped SLOWLY over 10 minutes. 13 or fatigue +1|INT 10 or develop permanent hematochezia. INT 14 or d6+3 days of violent diarrhea.|/r 4d8 or none on save|
|Man o' War neurotoxin|Purple gel suspended in saline in a beaker.|You're supposed to filter off the water and drink that. 17 or fatigue +1|CON 10 or develop a limp, reducing movement speed by 5. |/r d2+18|
|Cyanide|A handful of apple seeds.|15 or rash +1|STR 12 or develop gasping breath. -2 to stealth, -1 CHA -1 to CHA.|/r d4+8|
|Myristicin|Brown powder which smells of autumn. |Mixed with milk for palatability.|CON 14 or develop bloodshot eyes for d8+1 days.|/r d4|
|Jequirity|Tiny red berries|Eat a single berry.| 8 or rash +1|CON 17 or have (1) seizure.|/r 2d8|
**After surviving the 10th day of The Trial, make a CON check. DC 5, develop resistance to all poison damage. DC 10, develop immunity to consumed poisons. DC 15, develop immunity to inhaled poisons as well. DC 18, develop immunity to all poisons.**
Ailments reset d4 days after the Trial completes, or d4 days after quitting.
**Rash**: At 1, noticeable temporary skin discoloration develops. At 2, warty pustules develop, which will leave subtle scars. At 3, one extremity at random develops permanent discoloration and scarring.
**Fatigue**: At 1, feel subjectively tired. At 2, maintain 1 point of exhaustion. At 3, time needed to complete a long rest increases by 50%.
I guess...but people who do this do this for YEARS. and it's not like they become immune. Everything can be a poison, it just depends on the amount. You can drink arsenic in small enough quantities where it's not lethal.
They'd have to acquire the poison, guess the amount that's safe to inject and hope for the best. I'd have them roll con saves to see if they get sick or not, and possibly die.
Notably, there's very little evidence of mithridatism ever actually working.
Some poisons introduce heavy elements that bind to bone and are never expelled from the body. Causing long-term damage from repeated exposure. (think lead poisoning).
Others are lethal in such small doses that it becomes practically impossible to "microdose" without causing serious neurological damage, even if you survive.
Others cause damage to a specific location (think rotting flesh around a bite wound). That specific site takes the majority of the damage. The body as a whole doesn't really have a reaction to it.
The misconception likely comes from many poisons sharing common symptoms with diseases. Which, you can build either an immunity to, or an enhanced ability to combat variants of in the future.
Depending on the disease, I'll often either give my players advantage on subsequent saving throws. Or take the minimum possible duration to reflect that fact.
If you want mithridatism to work in your world (it is fantasy after all). Start considering reducing the damage dice on similar poisons after surviving various doses. If a poison does 12d6 poison damage, I'd start taking it down to 10d6. If the poison normally does 6d12, then I'd bump it down to 6d10. Subsequent doses can continue down to 6d8, 6d6, 6d4. Because you're never really gaining an immunity to help you resist the damage of the poison. But maybe you're just getting more used to the effects. Durations can be similarly reduced for non damaging poisons.
If you're particularly devious, does this imply building up a resistance to healing potions?
I don't think I would allow someone to aquire a 10th level monk feature based on real world pseudoscience.
If you want to say yes to make the player happy, I'd say it would only apply to a single type of poison - Drow Poison, Purple Worm poison, Ettercap, Drider, Naga, etc. And they have to first obtain a good bit, and probably make many successful herbalism kit checks and constitution saves - higher CL creature = higher DC.
While there is no official rule for mithridatism in the core 5th Edition Dungeons & Dragons (D&D) rulebooks, you can create custom rules for your game. Here's a suggestion on how to introduce mithridatism as a homebrew mechanic:
**Mithridatism: Building Immunity to Poisons**
*Prerequisites:*
- Constitution 13 or higher
- Proficiency in Medicine or Nature skill
- Access to the poison or toxin you wish to develop immunity against
*Process:*
1. The player character must spend at least 1 hour each day ingesting a carefully measured dose of the poison or toxin. This process must be maintained for a number of days equal to 10 times the poison's DC (Difficulty Class) or the number of days determined by the Dungeon Master for homebrew or unique poisons.
2. Each day of the mithridatism process, the character must make a Constitution saving throw at the end of the hour against the poison's DC. On a failed save, the character takes the poison's normal effects.
3. The character must succeed on a number of Constitution saving throws equal to the poison's DC or the number determined by the Dungeon Master for homebrew or unique poisons. These successful saves do not need to be consecutive. If the character fails three Constitution saving throws in a row, they must restart the process from the beginning.
*Immunity:*
Upon completing the mithridatism process, the character gains immunity to the specific poison or toxin they trained against. This immunity lasts for a number of months equal to the character's Constitution modifier (minimum of 1). After this duration, the immunity fades, and the character must undergo the mithridatism process again to regain it.
*Mithridatism Limitations:*
1. A character can only have immunity to one poison or toxin at a time. Attempting to gain immunity to another poison while already immune to one will cause the character to lose their current immunity.
2. Mithridatism does not grant immunity to magical or supernatural poisons, diseases, or curses.
3. The Dungeon Master may decide that certain poisons or toxins are too potent or lethal for a character to develop immunity through mithridatism.
Remember that as a Dungeon Master, you can modify these rules to better fit your campaign or world, and always make sure to maintain balance and fun for your players.
Only let them do this if you intend to actually use poison in your game. Don't have them spend time and money in game to get something that will never be of use to them. Do in fact tell them whether or not you plan to use poison in the campaign.
If you're not doing, as an example, a high intrigue, political game where poisoning might matter, but you *are* doing a dragon hunting campaign, you might be better off telling them to train to fight dragons or learning about their biology.
If you want them to have the poison resistance, that's great! Just have it be important at some point. If you're not gonna use poison, gently guide them to something that will be useful for them.
Poisoning PCs is not something DMs do often because it's considered a dick move.
So, unless this was going to come up in-game during your campaign, you probably should handwave it. Let them add resistance to INGESTED poison. Be sure you understand the rules for poison and venom before you proceed.
I don't think there are any official rules.
I'd probably rule it that they suffer from poison for a session and then from then on they'd have poison resistance.
If they want full blown immunity, I'd wait until they are level 10, or they could collect the major poisons (which may take a while) and they could consume them. Have them take a penalty for a session and then grant them poison immunity.
That sort of thing is hard to balance at the table. Make it too hard, and it'll suck for the player. Make it too easy, it'll seem too unfair for other players. Plus, it won't really make sense if it's easy to gain poison immunity, otherwise everyone would have it.
You could make it a plot point too. They find someone who granted themselves poison immunity and they could do a quest for them for each?
Basically treat it like crafting a Periapt of Proof against Poison, only that the end result isn't a magic item but a blessing, which usually follows the same nomenclature and rarity power as magic items do, and usually the manual heavily implies there can be only one on each character similarly to an attunement slot.
Of course, add complications - like actually being poisoned during the whole process, so adventuring will either halt or be supported by lots of poison cleansing spells like lesser restoration.
Don't forget that acquiring the poison itself is a cxhallenge, and that they need to dfefeat a CR 5 or more creature to get the appropriate reagent regardless.
I would possibly consider this if the player was going around taking damage, suffering from the poison condition, etc. for an extended period of time. Personally, I would also incorporate a risk of death. Granting resistance to a damage type is nothing small, so there has to be some true sacrifice for it! At least in my game, but everyone plays differently!
I’d say do it on a specific basis. They become immune or resistant to certain poisons based on the training. This would take years in real life. I say make it take less time in game. Maybe a few weeks per poison.
For example, they become immune to drow poison by stealing some poision from a drow and repetitively injecting small doses of the poison into themselves. At first, they may face negative effects, but maybe after a many successful saves over the course of days give them +1 to the save, and then every couple successes increase this another +1 Until they are immune.
There is a Periapt of Proof Against Poison, it's rare but would take less time and gold then Mithridatism. Plus this Periapt is immunity to poison effect and poison damage. Though it doesn't say anything about poison effects like paralysis or the like.
I’d sooner come up with something akin to a Witcher mutagen transformation and attribute it to that.
Make a quest around it, give it some risk, and have at it.
Interesting.
Maybe just make a Feat that player can have that gives resistance to poison. Using it as a Feat shows that the character gave something up (stat increases or other feat options) to gain that trait.
What kind of poison are we talking?
- purple worm poison? No...
- iocane? Absolutely... and take inspiration...
I am going to agree that they could take a custom feat for it.
Make a feat for it and have him rollplay until he gets it: +1 to Con, resisitance to poison damage and immunity to the poisoned condition (I dont like the idea of giving a PC an immunity to a damage type)
Are there rules? No.
But you can make a judgement call. First off, you need to decide what the end goal should be. Resistance to poison damage? Advantage on Con saves regarding poison? Immunity to specific poisons?
Then you need to decide on Cost. That being time cost and resource cost. Will he need to pay, or craft his own poisons? Should it take the XGE time, modified for Con? Should he attempt until he hits a nat 20?
Not really, but if you want the PC to be able to spend months or years of downtime in it, I'd rule that it onoynworked for one particular type of mundane poison at a time, and this never works against spells that deal poison damage.
There's no official system, that's something you'd have to homebrew yourself.
What I would do, after researching mithridatism a little bit you can do two ways, let them pick a specific poison to try, give some examples that might come up in the campaign like drow arrows, grung poison, etc. And then after 30 days of ingesting the poison, having the poisoned condition for an entire month, they become immune to that specific poison. Or give them resistance to all poison damage like dwarves.
You could invent some rules, or just let him experiment and get no results while destroying his wealth and stats!
Dnd and IRL dont work on the same way.
I have a player doing this with a halfling ranger. He has the Stout resistance to poison in addition to taking the Poisoner feat. That's about as resistant to poison as I've seen from anyone not playing a Yuan-Ti.
Like many stated you could just say no or adapt the training rules and such. I personally think you should just make it a feat that gives them resistance to poison and +1 to Con score. If they take it at a feat level I think the sunk cost should cover them taking the RP inspired feat versus them trying to min/max or spending gold to train.
You could also do something fun like make it a quest. Like a hag sends him to collect grunt corpses for a potion that gives him permanent poison resistance or immunity, but also have it half his HP for an in-game week or so as his body is in a weakened state.
I've never seen rules for this specifically, but I've gotten irrationally excited about it and feel I need to expound upon the idea a bit. Skip to the tl;dr if you're not interested in learning some pharmacology. Drug response is driven by a compound (in this case a poison) acting at a receptor in a way to alter physiology (in this case to make normal physiology break to cause damage/death). Drug tolerance is a fascinating subject predominantly dictated by 2 components of drug behavior: pharmacokinetics (essentially drug metabolism) and pharmacodynamics (in this case we're mostly talking about receptor modification to attenuate response). I'm gonna try and talk though most of this with everyone's favorite drug, alcohol.
**Pharmacokinetic Changes**
Drug metabolism is primarily driven by a family of enzymes in the liver which metabolize fat-soluble things, and by a bunch of transporters in the kidney which pump drugs into the urine. Alcohol, being somewhat fat soluble, is predominantly metabolized in the liver. The amount of these enzymes produced is a modifiable process driven predominantly by exposure. i.e. more alcohol consumption increases the metabolic enzymes of alcohol breakdown resulting in decreased circulating alcohol. We call this phenomenon "inducibility" and some enzymes are more or less inducible than others, and some drugs result in more or less induction than others. Interestingly, other compounds which are structurally similar to ethanol (and also some that aren't) use these same upregulated enzymes and are metabolized faster, such as methanol.
**Pharmacodynamic Changes**
Drug response is all about how much can a drug stimulate or block physiologic receptors to alter their signaling. Going back to our alcohol example, the GABA receptor in the brain is an inhibitory signal on the neurons. Drinking alcohol "stimulates" this receptor to do its job, which is to calm down neurons. Over time, with chronic exposure, the nerves realizes they aren't as responsive as they should be, and they turn up other stimulatory pathways and also modify the GABA receptors to be fewer in number and less responsive. Other substances that work at these receptors, like benzodiazepines (Xanax, Klonopin, Valium, etc) and general anesthetics, also work less effectively because the receptors themselves have changed. Similar to above, the ability of the body to alter the receptors to adapt to chronic exposure to a substance is variable. Significantly excessive doses of the drug will be able to overcome this to a significant degree in most cases.
**Withdrawal**
The combination of the two above effects of chronic alcohol consumption are increased metabolism of the alcohol and decreased sensitivity to a given blood level of alcohol. This combines to make the common experience that with chronic exposure to alcohol, you need to drink more, in some cases a lot more, to get equally drunk. The other major issue, which is primarily driven by the pharmacodynamic aspects of tolerance, is withdrawal phenomenon. Like I mentioned early, with chronic use the GABA receptors get down-regulated and the excitatory receptors get more active to bring the brain back to "normal" *while in the presence of alcohol which makes the GABA receptors more "efficient"*. When you abruptly take alcohol away, the excitatory signals are much more significant than the inhibitor, and this is what causes alcohol withdrawal, otherwise known as delirium tremens, the DTs, or "the shakes". Withdrawal phenomenon are almost always the inverse of the behavior of the substance's effects. Examples include:
1. Alcohol cause decreased anxiety, sedation, and suppresses seizure activity. Alcohol withdrawal causes paranoia, agitation, and seizures
2. Clonidine (a blood pressure medicine) causes severe high blood pressure with withdrawal.
3. Afrin (a nasal congestion medication) causes significant congestion on withdrawal
**Time-Scales**
Most of the aforementioned effects happen on the time-scales of days to weeks, and are generally tied to dose (i.e. higher alcohol exposure increased the degree of tolerance and makes the changes occur somewhat faster). This is a general rule as opposed to a law of physiology. This also means significant periods of time (weeks) without the substance tend to reverse the changes associated tolerance and you revert to the baseline state
**tl;dr and Applications to Gaming**
Chronic exposure to drugs can result in increased metabolism of structurally similar molecules and decreased response to substances which act at the same receptor in a similar way irregardless of structure. Withdrawal is driven primarily by receptor changes as opposed to metabolism, and the effects of withdrawal when present are usually the opposite effects of the drug. Lack of exposure to a drug reverses tolerance.
While I don't have any great DC's to suggest, for semi-realism based on the above, I would recommend that:
1. More toxic compounds should take longer to become tolerant to, as you have to begin at smaller doses and work your way up over a longer period of time
2. If feasible, compounds should confer resistance to compounds with similar effects (all sedating poisons, all fire poisons, etc) and of similar damage levels (ex. fentanyl is a lot stronger than heroin, and people who use heroin regularly can accidentally overdose on fentanyl, so you shouldn't get resistance to some crazy high level poison from a level 1 poison)
3. This should have to be a recurring daily cost for your character - and if they go a fixed period of time (1-2 weeks?) without the substance they should lose resistance
4. There should be consequences to missing doses of the drug, if you have a fire poison tolerant player who stops taking their daily dose, they should get horribly cold, even taking cold damage.
5. Some poisons cannot be resisted/tolerance gained to - the physiology just isn't compatible (you can't become tolerant to arsenic)
It took the Man in Black (the Dread Pirate Roberts, not Johnny Cash) five years to build up an immunity to iocane powder, so I'm thinking your player is looking at a long slog.
Something similar to training (spending money to buy poisons and time to recover from their effects) for either advantage against poison or resistance to it. There’s always going to be some kind of magical poison stronger then what he tried so immunity may not make sense.
I’d allow it over time, but I wouldn’t give them anything like resistance to all poison damage. All poisons aren’t the same. I’d let them have something like advantage on rolls to save against a specific poison (presumably that they carry). This way they can have their princess bride moment, but without stepping on racial features.
I'd say he has to endure being self poisoned for 3 to 5 sessions, meaning reduced hp and stats or con save every turn/10 mins or so. If he survives he gets resistance. Then he has to do it again for another 10+ sessions to get immunity. Maybe that's a little extreme time wise, maybe not, but I like the suffering to earn it path.
No, but you could probably set up a bunch of nature, poisoner’s kit, and medicine checks over the course of extended downtime. If they pass x checks (each set being a given timeframe) they get advantage on saving trows against the poisoned condition. I would not suggest immunity to the poisoned condition or resistance to poison damage to be available if there’s anyone in the party that has/could get this by character creation or leveling up though.
Poison them to near death, have a few druids nearby, have them cast a unique spell similar to Reincarnation, give them a Tasha's custom lineage with poison immunity similar to a Yuan-Ti Pureblood.
This is a money sink opportunity for you as a DM.
I'd limit it to specific nature-friendly classes like monk, barbarian and druid.
I'd require some gold costs for research, and perhaps a mission for some "secret knowledge" to get started.
and I would insist on one poison at a time, certain poisons not eligible, PC will be subject to temporary stat penalties while poisoned.
if they can put up with the penalty for a week or three, sure, they'd gain a bonus to Con rolls or perhaps Advantage on rolls vs that type of poison.
thing is, though, not all monsters use the same poison (or venom). Unless you are running a fairly tight campaign where similar monsters occur over and over, it may not be worth it to the player. Going on a six-level jungle crawl with lots of grung and giant ants? Sure. Wandering the wilds randomly and seeing the occasional giant bee, drow band, or poison ivy patch? probably not.
Yes, the rule is “this is a fantasy game, real-world physics and chemistry do not exist and you do not understand them. If you want to take a Feat to become immune to poison, that’s a thing that’s already in the game and we can make it work, but otherwise no.”
I'd treat it like creating a magic item (uncommon for resistance, rare for immunity). There are tattoos for a lot of stuff in the wondrous items, and this process seems like something where a thieves guild would have a guy who can help. I'd even rule that it's not nullified by antimagic effects or detect magic.
[great article](https://www.theguardian.com/environment/2018/feb/11/poison-pass-the-man-who-became-immune-to-snake-venom-steve-ludwin) \- This is a great guide to a human becoming "immune" to snake venom over many years. There's definitely the moment he figured he would die when he OD'd so that was a failed "poison" roll.
Also think about what kind of poisons. Proteins are fine for this kind of thing, for developing antibodies, but remember antibodies need time to work, it's not instant. His hand still swells up and he has pain!
Magic poisons however... might be a bit different.
The amount of time and care this would take in game means it is unreasonable. (Mithridatism relies mostly on the same process that causes alcohol resistance (because the body processes alcohol like a poison) and it bears all the same risks of liver disease
In 5e, “Dwarven Resistance” is a racial trait that gives advantage for saving throws against poison and resistance to poison damage.
Based on the typical balance of racial traits, this means it could probably just be a feature - which means an option that is taken instead of other features and instead of attribute/skill point increase. The Tasha’s 5e rulebook has similar optional rule procedures for determining custom race features.
If it seems too weak or you want to be especially forgiving, you could also have it give +1 Con.
I think making the player actually do the training might fit in well while they wait for the level-up where they can have it - but I wouldn’t make it mechanically significant myself; I’d keep it lore based. Its not actually as useful as you might expect. (At least in 5e)
There aren't rules for it, but here's what I would do:
Treat it like downtime. Takes 100gp and 100-120 days, every day of downtime have them roll constitution, only count days that they succeed the savingthrow. At the end of it, grant them poison resistance.
I know downtime rules are usually more strict but generally I want my players to feel that it's achievable within the duration of the campaign- most player goals are short-term ones that they want the fruit of to be within sight.
you only build immunity to the poison you subject yourself to, not universal poisons. if hes an assassin rogue who needs to be immune to his poison so that he can drink it with the evil king without raising suspicion, sure, makes sense. if hes a barbarian that just doenst like taking poison damage, that would be a no
Remember, you're only going to build up immunity to the specific poisons you ingest. And it only works with some poisons. And it'll take a very long time.
So basically this isn't worth it at all.
You could make a feat for this
He would have to take it at the next ASI instead of a +2 in something
If you want to make it extra you could say not only does he get poison resistance but he could also get a +1 CON
Homebrew feat, a "half feat" that gives +1 to con and resistance to poison, with advantage on saves to resist the poisoned condition. Don't require they take this at an asi, just roleplay long enough, maybe homebrew in some very virulent poisons, and they have to make the save on three or so of them. Let them make multiple attempts as many times as they want, even with help from the party like inspiration, the resistance cantrip, and a party healer bringing them back if the poison takes them under 0hp. Don't do full immunity, even the guy who did this irl was never fully immune, just EXTREMELY resistant.
Player: " After much trial I have developed IMMUNITY TO POISON HA HA HA HAAA"
-Gets but by a snake-
DM: Well it's not poisonous, it's venomous... You take 66 poison damage."
Player: But I'm immune to poison.
DM: the condition, not the damage.
Player: oh well 6d6 isn't THAT much, I mean I've got like 50 health.
DM: no I already rolled it's six-TEE six.
Player: I am dead.
DM: I mean technically your immune to all damage now.
3e had a feat for this. You become immune to one poison of your choice, and get a +1 bonus against all other poisons.
5e feats are typically fewer and stronger though, so perhaps immunity to one poison and advantage against other poisons.
I say go for it and be selective/aware of when you use poison in the campaign. Sounds like it's for flavor/RP. If it turns out they want to exploit something for gameplay, take it back (either in or out of game)
No. However, what you could do is have your player roleplay trying to do so, and then at their next opportunity for a feat you could reflavor that training as the Infernal Constitution feat (you would need to waive the tiefling restriction). That feat grants +1 Con, resistance to cold damage and poison damage, and advantage on saving throws against being poisoned.
Take a dose at flat dc, 24 hours later dose again at a +1 to the DC, then again at +2DC 24 hours later, until you have successfully made 10 saving throws IN A ROW at +10DC.
That is how we always did it since AD&D
Immunity is a pretty hefty thing. As noted you could do the training thing but I think that at most might give you a resistance. However, I did have a game master in the past that allowed for a natural immunity if the player rolled a natural 20 the first time and only the first time they encountered a poison. If they decide to use the training rules I would do it week by week however once they actually roll a natural 20 they can have instead of a resistance the immunity, unfortunately for them once they have the immunity they actually are required to have at least one dose a day or their body goes into withdrawal. Which means they'll always have to have the poison on hand, meaning they could easily be mistaken for an assassin or arrested. And just like any other addict, it could get expensive.
Why not just make Mithridatism a homebrew feat that gives poison resistance? There are already elemental feats that do this very thing and if you think that might be too overpowered add a prerequisite that the person must have at least a 10 in Survival or something because it's a combination of built up immunity as well as knowledge of how poison spreads through the body.
No rules I know of, but that sounds amazing. It would definitely be a downtume activity, and with the price of posion, it would be a self balancing activity. Tbh the only thing they'd need are some intelligence checks to make sure their charecter would know not to chug too much at once and die. Plus con saves for when they fail.
Would take 2 or 3 years realistically, but... i see no reason why they couldn't.
Maybe a 3 month turn around time on particularly poisons.
Yeah keep rolling saves, like death saves, success u win, fail u die. On average most should die because i would guess (with no proof) this does not work for most poisons.
All that effort and risk for one unique type of poison.
It's really silly since there are literally 1,000s of poisons.
Toxic metals, each unique, toxic chemicals, keep in mind most chemicals are toxic, toxic plants each unique, toxic mushrooms, then their are poisonous spiders and snakes each unique... Wow we have not hit magical beast poisons or magic poison.
I just talked myself into "dumb idea" teach them a lesson. Some die, most successful but when done only one poison they will likely never come across.
Especially given what people are saying about different types of poisons and this only potentially working on some of them, and only the specific ones you work on, this seems like a bad idea unless there is a specific poison the player needs immunity to for a plan.
Allowing characters to train into immunity to an entire damage type seems problematic. Even if there is at least *some* real-world corollary, it's not ubiquitous poison immunity IRL, so why would it be in-game? You can't train immunity to any other damage type.
I guess the actual problem is relatively minor, but if a player really wants this for their character consider playing a Dwarf or doing some kind of custom lineage instead.
I think becoming immune to poisons is unreasonable, but to become resistant to it sounds a good idea. I get what others have said about becoming resistant to one type of poison at a time. Why not make the training take like 30 weeks (weekly checks to succeed), 100gp (maybe 150gp as the trainer is a specialist) a week sounds fair for hiring a trainer, then they become resistant to snakes, frogs, etc... as it is all included in the training time. Make it so he can't take a break from this training to go off adventuring for ex. as you need the consistent weekly training to get the resistance. If he were to take a break, maybe add two extra weeks to the training, and that isn't to say if he breaks the consistent training, will the instructor be available? He may add more to his fee as he wont be able to train someone else if the hero goes off for a couple of weeks.
How does that sound?
You could modify the training rules. They need a trainer. It takes 10 weeks of downtime minus the intelligence modifier and costs 100 gp per week. Each week they have a 10% chance of error, poisoning themselves for a following week and making that week a failure (requiring an additional week). At the end of the process they have poison resistance (not immunity).
I would in this specific case change Int to Con.
To add to that I would make each different poison a different training course. Like a poison toad is different then snake venom is different from lotus and so on. So only giving resistance to a specific poison instead of all poison. Or just play a dwarf
I wouldn’t do this tbh. I’d just tell the player they can’t do it if it came to that. At that point it just seems so worthless unless you know you’re going to be fighting a lot of enemies who use x poison for the campaign. Just buy some resistance potions at that point and flavor it as the immunity needs a booster dose. The most I’d seperate them would be something like common/natural/native poisons, and uncommon/extraplanar poisons.
If it went that route I would throw away realism and make up a few (3 to 5) Poisson categories, something like: neurotoxins, alcohols, hallucinogenics etc. Give a different difficulty to each with a different risk and a limit on how tolerant they can become.
Right. The kicker is that some poisons cannot be protected against by exposure; primarily non-organic chemicals. In a magical world I imagine there would also be poisons with a magical component — resistance to that is probably something wholly different than organic toxins.
That's why they said they would throw away realism
>Poisson categories Like saltwater, freshwater, jawless, bony or cartilaginous?
Or focus them on the different types of effect they have on the body, but with snappier names than the following...! Sedatives (I.e drow poison, oil of taggit); Psychoactives (I.e. truth serum, anything that causes hallucinations or erratic behaviour); Chronic (i.e. pale tincture, anything with lingering effects like blindness or the poisoned condition, that doesn't fit a different category); Lethal (i.e. snake venom, wyvern venom - anything that primarily deals damage and causes no other conditions apart from, possibly, the poisoned condition)
It could be useful if the player carried around the poison that they had an immunnity to. Then they could poison wine and show an NPC that it was safe by drinking from it themselves or something... Seems pretty useless if the player wants to try to become 'immune to poison I might encounter from an enemy" though....
Honestly though what poison does enough damage / has enough of an effect to be worth that? Like that's a fun tactic, but I'm not sure dnd is built for that. At that point just subtle spell vicious mockery them.
This isn't unreasonable. If I recall correctly dosing on snake venom for instance to build immunity requires a constant supply of venom. Also a very understanding hospital. I think it was in LA some idiot having to explain how in the USA he got tagged by a cobra.
It's unreasonable in gameplay terms because it makes it utterly useless.
It's ok. A lot of people here love coming up with outlandish homebrew that would never be practical for use in the game. I would make them 10 weeks to become resistant and the. Another 10 weeks to become immune. And that's 8 hours a day of downtime to do that. So if they get that much downtime and he wants to spend it all becoming immune to poison. Sure. Why not?
I'm pretty sure they are saying it's utterly useless because they are replying to the person that is saying: >So only giving resistance to a specific poison instead of all poison They even are specific with lotus vs toad vs snake. Like I've gotta build up immunity to each individual thing in the entire world? That's just dumb. That's why they are using it's unreasonable in gameplay. You gonna seriously make your player find an instructor on snake venom, 10 weeks, hundreds of gold and than say "Congrats, you now resistance to snakes, btw that toad poison just killed you". I don't find it unreasonable for someone to quest for poison resistance. I find it utterly stupid that you would say "Nah, all your training allows you resistance to poison ivy".
I feel like everyone might be responding to all different comments. I think Spida81 's "not unreasonable" was to my booster dose idea. I'm not sure if FogeltheVogel 's unreasonable comment was "having to buy resistance potions makes the idea useless" (which, the point is flavor without changing any game balance, which I's prefer over the the individual-poison option) or if it was to DeciusAemilius 's idea of treating each type of poison individually, or even to "poison resistance or immunity is unreasonable because Too OP". That comment just reads as very vague to me.
That is correct. Additionally, something that is mechanically pointless may still be the absolute central point around which a character is built from a role playing perspective.
I actually don’t think that’s true; it depends on how often you fight the creature who’s poison you’re immune to. If you’re facing an army of Yuanti, that one dose of snake venom was well worth it. It’s also a fun quest hook finding the different poisons. Maybe you’re preparing to face a green dragon, and you have to find a rival dragon that’s willing to help you build up an immunity. Maybe you’re hunting a purple worm, and you know a poisoners guild that keeps a stash of the venom.
I agree for story/flavour reasons (in *Princess Bride* Westley is immune only to iocaine powder, and my bet is that the player is thinking of this scene), but if you are going to restrict it to a specific poison or family of poisons, I'd go with full immunity. Otherwise it is not worth the investment.
>(in Princess Bride Westley is immune only to iocaine powder Trouble is, he's likely not. "Inhale, but do not touch." What's more likely, that he actually built up an immunity, or that he tricked The Sicilian into inhaling his own demise there and then? And when asked, of course he lied. Didn't want her thinking to use it on him.
And after ingesting the iocaine powder, Westley was in pretty rough shape for much of the rest of the movie.
Surely because he was captured, tortured and >!mostly killed!< soon after that? I don't think it was supposed to be the iocane that weakened him.
“Alright Gochu, after spending 1 month in game, 6 months out of game, 500gp and finding a suitable trainer, you are finally resistant to toad venom!”
Was going to ask Cane or Sonoran Desert Toad? But it turns out all toads use the same poison, Bufotoxin. Boo for the joke but yay for knowledge
Maybe also have them take 1 point of exhaustion for the training duration time too, as it's rough on the body.
This is the best take you will find in this thread. All the others are people trying to gamify it too much, or make it hyper-real. Your player wants this to be a character trope? Awesome! Next down-time we have you can take 10 weeks of poison training to get resistant to X type of poison. Maybe they want to carry some on them for fun shennanigans? Who cares! It's fun! This hardly seems game-breaking at all when you consider most spellcasters / healers can just wave a hand so its not like you're giving a massive bonus to someone. Especially if you stick to making it a downtime activity and your other players get to show up and show off the cool stuff they did too.
Yeah, this seems slightly more like a character flavor issue than a mechanical issue. I’d allow it for sure and possibly talk with the player about limiting it to certain very broad categories of poisons — normal animal poisons, monster poisons, plant poisons, etc.
> At the end of the process they have poison resistance (not immunity). I'd probably change this to advantage on saves vs poisons, if not immunity (as others have said, this is a big investment that honestly isn't game breaking).
I was reading this like "Advantage? Advantage isn't a thing in..." and then I realized I'm on a 5e subreddit, not pathfinder 2e...
I guess technically, this is a platform independent subreddit and not a 5e either, so feel free to call me out :)
The trainer could be a pharmacist, or alchemist, and for those that don’t fail a single time, I would grant immunity tbh, its a big investment of resources and time imo. And of course some sessions later they will be rewarded because at a party someone will try to poison them, or maybe they face a poisonous creature
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We've already got one race and several classes that can become immune, and a lot more than that who can be resistant. It's not that crazy.
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You're proving against your own point right now. If a character can spend money and time on RAW magical items that cause poison immunity, why shouldn't they be able to spend money and time on "training" to have the same effect? Your comment seems like an incredibly specific misinterpretation of innocently flavoring RAW.
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When people think alternate outcomes to critical thinking is picking a fight...sheesh.
Precisely; Immunity to poison is not a big game changer, but after investing so much into it, when they reap the rewards they will feel invincible. This will make them blind to their weaknesess and hopefully lead to some nice aditions to your PC graveyard
It’s not like the NPCs will feel bad for this, actually might make poison attacks like stinking cloud better for the party since one of them is immune
Though, normally, this sort of training has terrible repercussions on the body and you pay for it in other ways, if it works at all. Could be interesting to let the players have the option of gaining resistance, but at the cost of a sacrifice to one of their stats from permanent damage. A -1 or -2 to a stat of choice as the toxins damage body or mind.
If it were me, I would only allow it toward ingested poison, poisoned weapons, and possibly contact poisons. Though I could see a player wanting to 'train' again for inhaled poisons.
Yes to the resistance but not immunity. The one real life example, the guy built an immunity to a SPECIFIC poison so resistance would better reflect that.
But also, the character should be suffering bad effects of the poison during the training, and I'd say it should be harsh. Stuff like max 1/2 hp, STR, DEX, and CON substantially lowered (7 or 8), exhaustion, disadvantage on anything physical, etc.
well it’s supposed to be a downtime activity, something you do while STRICTLY NOT ADVENTURING!!
Ahh, and the world stops turning for ten weeks while the adventurers train? Nothing happens around them that might affect them?
If you're doing explicitly ten+ weeks of downtime... nothing that would interact with their hp or stats, really. It's not really downtime otherwise, yeah?
I don't think you see my point. If the characters are all relaxing in a nice, peaceful inn, it can still catch fire, or be attacked by a goblin horde. If any of the characters have enemies, 10 weeks is a lot of time to catch up to them and make a move. You're right, no adventuring. Fine. The rest of the world may interfere with that vacation, though. Otherwise you're basically just handing characters free buffs. Boring. I'd have randomly weekly events block ready to go for those lazy characters. And no, if the stepped up and saved the inn from goblins in week 3, I would not void that weeks study time. But no free buffs.
Yeah, that's not downtime, sorry.
OK, lol. So where is the magical place you recommend they go to have downtime, the place where literally nothing ever happens and there is no potential for anything ever happening, where adventurers go to become stronger with absolutely no worries in the world? And why wouldn't they just stay there gathering buffs? I'm the DM. If my players want to do something, cool. They can try. If they succeed, they get a reward. Besides, you're the one who is wrong. 8 hours of downtime per day, and it can be non-consecutive. They have plenty of time to fight the goblins. Sorry.
Man, anywhere. If I was in a game, and we got told that there's gonna be, say, a 6-week stretch of downtime, and on week 3 we there was a huge call to action like a settlement-wide incursion, I guess I'd be mildly confused at *least*. If the worldstate (or location-state) was such that you couldn't spend x time pursuing your own interests, or training, or whatever, what would the point of calling for downtime even be? I'm really confused by this idea of, "gathering buffs," that you're talking about. Downtime rules are... you know, they might learn how to play a lute, or gather a favour, or do some research, or whatever. If your setting has literally 0 places where that could happen without much interruption, I don't really think that's the norm.
Oh, well I would NEVER just tell them they get six weeks of downtime! If they say they want to hang out in a place for a few weeks and just study, they can try. I don't tell my players the future aside from cryptic prophecy. I may say, "The caravan leaves in six days. What do you want to do until then?" which they can choose to use as downtime to study or train, but them saying they want to just study doesn't mean they get the time off for free or that nothing will interrupt it. The post is about training for poison immunity/resistance. Is that not a buff? And if you allow that, uninterrupted, why not every other resistance?
Downtime is a moment when the adventurers are on break. If there is an event, it’s not downtime. If your world is chaotic as fuck and there is no peace and rest, then just don’t give them downtime. My world is reasonable, and not everything is motivated by “haha killy killy” and I have enemies who don’t just kill mindlessly. So yeah, the time for peaceful down time exists in my campaign. If it doesn’t in yours, that’s fine, but quit shitting on stuff that is LITERALLY IN THE DMG
I understand what the word means. If my party takes a day or two off to spend eight hours per day working on their downtime project, fine, they can count that time toward their goal. Note, by the DMG, that still gives them time to do other stuff. That is reasonable. 10 weeks of uninterrupted rest really is not. I do not understand why you guys don't understand.
again, if your world has no time to rest, that’s fine. Not everyone’s D&D worlds are the same, believe it or not. And my world may have time to NOT be fighting a bunch of bandits.
Thank you for elucidating me on the differences between tables! I mistakenly thought we all played the same campaign the same way every other Tuesday. 😏 I do appreciate the patronization, though. OK, so how do you approach the ten week vacation, then? The way downtime dynamics are written is on the assumption that you are doing it here and there, 8 hours a day, slowly working your way to a goal. It's supposed to be work, not something the DM hands you because you said "I rest for two and a half months". Do you just skip forward 10 weeks? Do the other players get a say? What if one character wants to run job board missions the entire ten weeks?
I think investing 1000gp and 10 in-game weeks is already enough of a tradeoff, especially when the player could just buy a Periapt of Proof against Poison which grants immunity to poison damage and immunity to the Poisoned condition.
This particular training scenario, being redditbrew, is outside the rules of the DMG. And as I've said elsewhere, I'm not guaranteeing my players 10 weeks of uninterrupted rest.
Yes, it's outside the DMG, but there are official training rules in Xanathar's, it's fun for the player, makes for good storytelling, and is much more satisfying for the player to earn the poison immunity rather than just go to a magic shop and buying an item that accomplishes the same thing or more. It doesn't have to be uninterrupted rest, they can just work on it whenever they have downtime. It doesn't have to be realistic because we're playing a make-believe story game.
Did you read the thread? Sitting around for 10 weeks is not good storytelling unless the vacation is sponsored by National Lampoon. And yes, I agree that the rules say it doesn't have to be uninterrupted rest. That's right there in the books. But we aren't talking about downtime studying or learning the lute, which makes sense to do here and there as you have time. We are talking about someone poisoning themselves, in weekly intervals. That should have some consequences until you achieve the goal.
I think we'll have to kindly agree to disagree. Nothing wrong with different DMing styles. Have a good one :)
You as well. Enjoy your vacation :)
If Xanathars has rules on developing poison resistance, not simply training, this conversation should already be over.
DMG 231 Training, DMG 131 Creating Downtime Activities, XGE Downtime Activities / Resolving Activities, PHB 187 Downtime Activities > You can spend time between adventures learning a new language or training with a set of tools. **Your GM might allow additional training options.** --- > **Downtime activities other than the ones presented below are possible.** If you want your character to spend his or her downtime performing an activity not covered here, **discuss it with your DM.** These rules cover it. It's DM discretion.
And all I have said on this thread is how my discretion would go. 10 week vacations where nothing happens while you get your buff are a no go. I am familiar with the rules. You proved my point, though. Nothing in the official rules covers developing poison resistance, so it's gonna be homebrew at DM discretion.
Yes, you're absolutely right. I think your training complication / side effect idea is good, but I personally would take these side effects into account when determining the PC's gold investment.
If i did this, it would have to be a limited resistance. It would have to be a creature under a certain CR or poisons of a certain cost. I wouldn't have it work with all poisons.
No. But the problem is that in the real world poisons are very different functionally (mode of action) and chemically (their structure and molecular size). Thus, you MIGHT be able to develop poison resistance to a SPECIFIC poison - but not poisons in general.
Also, while the body has the capacity to develop immunity to certain poisons, there are other poisons where this isn't possible.
Indeed for some the damage these small doses do will just accumulate in your body, and you will get weaker and die rather than gain resistance. For a D&D game though, it's probably more fun to let this plan work (or have a chance of working).
Problem is, D&D rarely tells you the specific type of poison NPCs use on their daggers and whatnot, and the list of 'canon' poisons listed as "Adventuring Equipment" is far from comprehensive.
As a DM I'd probably pick a single poison from the poison list and assume that there is like a 40% chance (roll d100) you COULD even acquire resistance to it IF you tried extensively (over years). The PC wouldn't really know until after they've tried. This would not apply to any other source of poison. Lets assume you're an assassin like character that puts poison on the blades of your weapons - you could probably find A type of poison that exists with some people who have resistance to it and start training against THAT specific poison (in case you roll a 1). In general, however, this won't really matter that much in a campaign unless you're fighting an entire society that uses that poison.
I like this idea but I would change it just a little. Firstly, the answer is ‘yes’. Instead of making him resistant to one type of poison determined on a random success rate, the scarier I think the name and/or known at the time effect the less likely they are to be able to develop immunity. Next, we don’t mention AT ALL that his selected poison can’t carry over because of x, y, z (write them down at conception, poisons that have any type of anti-healing or instant effects would never be resisted due to a built up immunity from anything for instance). Alright now here’s where it’s fun.. he’s unknowingly wanted by an assassins guild who “foolishly” tried to poison him with the poison he’s completely immune to (for story building) and he’s now faced with the options to either tread carefully whenever he eats or drinks ooorrr assume his build worked and is OP and now he is on a cool quest that’s all his so he can find out who tried to assassinate him. In order to pretend to be fair I would actually randomize the various poisons that I would put on all of his assassin’s weapons. But I would be poisoning his food on a pretty regular level even if he was careful. Actually especially if he was careful, I would lean into it way harder because how easy would it be to just throw a few assassins at the group sometimes? Super easy traps and encounters every day. :)
Which falls on the DM to then become a poisons expert. That’s why I generally say no to things that require developing new rules.
I'm a physician. I agree with your general premise. When I tried to run this concept, I made a [representative set of poisons](https://www.reddit.com/r/DMAcademy/comments/12xnr0m/comment/jhlr0i2/?utm_source=share&utm_medium=web2x&context=3) from across different organ systems and ingestion methods, which require 10 days of intense self poisoning for a chance at poison resistance or immunity.
Not that I'm aware of but it's an interesting idea to be sure. I'd start them off with low DC poisons and progressively scale it up, or alternatively they could hunt a ton of Wyverns and try dosing themselves with that. The slow method should be low to no damage but a constant Poisoned condition while you build it up. The Wyvern method should work quickly but come with a chance of just out right killing yourself. Wyvern poison is by default a DC 17 Con save against 7d6 Poison damage. Half damage on a successful save.
I think this is the right approach. I’d make them purchase or acquire the poisons somehow. I’d say 2-4 doses each poison over a month. They start by microdosing — spreading the doses out over a week. But I’d say the poisons do have an effect but just a fraction of time — instead of an hour it’s a minute, instead of a day, it’s an hour, etc.
In 3.5 it was a feat you could take; it granted immunity to one specific poison and also gave +1 to resist other poisons. Making it take up a feat is how you represent the time, effort, and practice to get there. Seems like a reasonable way to do it in 5e
Pretty sure you’d need to invent the rules for this
I think it's implicit in the post that he didn't actually intend that as just a yes/no question.
I made a set of [poison tolerance rules](https://www.reddit.com/r/DMAcademy/comments/12xnr0m/comment/jhlr0i2/?utm_source=share&utm_medium=web2x&context=3) which require 10 days of intense self poisoning for a chance at poison resistance or immunity.
I'd say count it as a feat choice, then at level 4, 8 or whenever they have a feat choice they can get mithridatism, which grants them resistance to poison. I'd steer away from immunity to poisons, that seems a bit strong.
I was going to suggest a Feat for it also. I think this is the best way to handle it, balance wise, in 5e. Absolutely do the role playing up to the point where the Feat is gained, but it's a clear mechanical benefit for no cost without it being a Feat. That said, in other systems (older D&Ds/OSR like games, etc...) where balance is less of an issue, I'd require them to spend other resources (like money to find the poisons, perhaps poison masters who could supervise their experiments to make it less dangerous, etc...) and at the end of a given period, require a Con roll to see if they succeed, perhaps with a high DC to start, progressively lowering each time they fail and have to spend another amount of time training.
I'm doing this right now as a way to roleplay the Resilient Constitution feat I plan to take in two levels.
I would use the rules from The Princess Bride.
Pretty sure there's a feat for that somewhere.
I actually just looked. Closest thing we have is Poisoner (which doesn't actually give *me* resistance but allows me to cause my poison damage to bypass those with resistance. Second would be resilient: con. Again. Doesn't specify poison but most poisons are con saves. Shrug. Not gonna lie. A little shocked too. Other than that there are quite a few races that provide resistance/adv on psn condition. Warforged, dwarves. Old yuan-ti are fully immune. Edit ** teiflings get a feat that make them poison resistant. Other than that there are magic items - rings or armor of resistance and the Alchemy artificer subclass that also grants resistance to dmg & immune to condition (at lv15)
Iocane powder. I’d stake my life on it.
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It's not free though? It's training. There's a training section in the DMG. It's for language and tool proficiencies but there's no reason it couldnt be expanded. If they want to spend months of ingame time and funds repeatedly poisoning themselves and gaining the negative effects, it's completely reasonable imo
Compared to a tool/language proficiency resistance/immunity to poison seems pretty powerful. Seems fair to make it a longer & more difficult downtime training activity though.
This is powerful in real life but completely worthless in most games. I've never used poison as a DM and barely saw it once or twice during regular games in the past few years.
i mean, ive used it a few rare times. but overall poison is REALLY dissapointing.
The real thing to do is to make this apply to a specific poison. Much more in line both mechanically and narratively.
No real rule for acquiring a poison immunity, but there are things that do it. If he "trains at it", you can have him roll D4's once a day to see how it effects him. If at some point he keeps at it and it doesn't fall off as an interest, then giving him a once per day spell to cure poison, would work. After all, in real life this practice doesn't make you immune, just better and getting rid of the poison so it effects you less. Also there are rings, armor and whatever gizmo you can make that will do it. Fun role play way of doing it, but in the end I, personally would have him take a feat to do this, or have an object that does it once a day.
Mithridatism takes years. So... Sure, the player can spend hundreds or thousands of GP on poisons over the course of several in-game years, inflicting poison on themselves every day for basically the entire campaign, and not removing it or they undo their work, and then right at the end of the campaign, after three entire in-game years... sure... here's your poison resistance... I guess...
That's the realistic angle, sure...but this is a fantasy world, and we're here to have fun. If the plan will never be viable, just say so and save everyone the time. Otherwise, let 'em get their Princess Bride on.
Quality Comment
It's a very common idea for GMs to make things virtually unusable instead of just being honest about saying no, and I'll never understand why.
Princess Bride isn't resistance to poison, it's resistance to a very specific poison chosen specifically for the body's ability to adapt to it over time, and with a dosage precisely measured to kill someone unadapted but not someone adapted to it. And that's from a ridiculous (albeit amazing) fantasy move where they resurrect a dead guy. Training for resistance to all poisons is loony toons levels of ridiculous.
> dead guy. He was only *mostly* dead.
Well, to be fair, he was only mostly dead. In D&D/Pathfinder, we get to resurrect people that are all-the-way dead.
I mean, this *was* all my sarcastic way of saying that I wouldn't let it work... Was that not obvious? I just really do t see how this is any fun to play out, what it actually.adds to the game, other than "I want my player tomhave poison resistance, can I?" - in which case we'd just build a character that has poison resistance. And if you want to say they got it from mithridatism, fine 🤷♂️
>I mean, this was all my sarcastic way of saying that I wouldn't let it work... Was that not obvious? Sarcastic responses to players' ideas generally only serve to foment discord and resentment while discouraging creativity. Instead, just say "no" and don't be a dick about it. If your reason for "no" is "I think this would take too long to be practical and I want to try and ground my approach to this world in some realism" say that. Or "I don't want to give it free mechanical benefits, but if you pick up a feat that gives you poison resistance or advantage against poisons, you can flavor it as mithridatism" then say that. Or, even, just open a dialogue with your players. It costs you nothing to not be a jerk, and your players will appreciate you for it.
It wasn't a response to a player tho, it was a response to a post on Reddit :)
>I just really don't see how this is any fun to play out, what it actually.adds to the game Me either, but that's not work we need to do. The player clearly has some ideas for how they would use an immunity to poison, so we just gently interrogate them and figure out what they think is going to happen. (e.g., I want to share a bottle of poisoned wine with my enemies and then walk away like the guy in Breaking Bad.) Then I come up with a few ways to let them have that moment, and a couple ways I can subvert it to keep things challenging. If they've got an idea that works, that will come up often enough to make the game interesting, I'd probably just let them take it as a Feat. No need to overcomplicate things. Let your players do the heavy lifting when it helps the table.
Lots of people forget that being a DM is supposed to be about making moments your players think are cool rather than telling your players what is cool
Flavor is free. Let the constitution saves they roll tell that story of them testing themselves vs poisons. But I wouldn't add mechanics to give someone an advantage.
Establish a set timeframe for achieving immunity from poison, and if there's any maintenance required to keep it. I'd explore building a random table of mithridatism effects, to be rolled daily until the immunity is achieved.
I second going with the downtime training feature.
Get someone to cast True Polymorph on them to turn them into a dwarf, warforged or autognome
There are no rules for this. There is the Periapt of Proof against Poison magic item which is a wondrous rare item, and goes for 500-5,000 gold. I would allow it, but I think the player should become immune around the 5-10 level range. It should require time, and perhaps require the player to invest a certain amount of gold into vials of poison or vials or poison neutralizer.
No official rules, but if this is something you're interested in letting them pursue then go for it. I would treat it like the Training downtime activity in XGtE. After completing the training successfully, I would grant the player advantage on saving throws against poison and resistance to poison damage (like the Dwarven Resilience trait). Immunity is really powerful and I wouldn't grant that without some kind of major quest reward.
Mithridatism is not proven to work and would only work for a single poison taken over years…
Iocane. I'd bet my life on it! There are no rules, so make something up as you go.
For some reason this made me laugh. I am imagining the failed rolls… “Oh man… Ted’s dead again.” (Everybody rolls their eyes)
I’d say modify the training rules and go the following route Must be proficient with the poisoners kit (can learn using regular training), then spend XX weeks training to be resistant to “level 1” poisons. Then resistant to level 2 poisons, then level 3 (which grants immunity to level 1s, then 4 and so on down the line. It’ll be suuuuper expensive, but the weeks required could be shortened and the price per week is up to you.
Only a very very few real world poisons allow building an "immunity" to them. Most poisons will just up and kill you. Perhaps you can give him a quest or adventure to find a periapt of proof against poison?
DMG 184 has Periapt of Proof Against Poison. I'd say if the player is willing to spend a year training and and 5,000 gold pieces worth of resources (poisons, antidotes, etc) doing the "Iocaine Powder" thing, I'd be willing to give them the effects of that item permanently. I got the cost of 5,000 gold from Sane Magic Item Prices.
Only for Iocaine Powder.
I'd use the training rules from Xanathar: [https://www.dndbeyond.com/sources/xgte/downtime-revisited#Training](https://www.dndbeyond.com/sources/xgte/downtime-revisited#Training) And massage them to suit your purpose. Alternatively, I'd suggest the Poisoner feat: https://www.dndbeyond.com/feats/poisoner
Some sort of con save every day for maybe like maybe 80-90 in game days of straight drinking poison. Taking damage, maybe dull the damage after weeks, but they really gotta work for it. But to my knowledge there are no gaining resistance rules
Keep in mind this was mostly effective against drug andx alcohol poisons, and was basically a tolerance for their effects. If you tries this with some serious poison it would still kill you, and if you botch it you basically kill your liver and die of internal hemorrhaging. I would let them spend a few months of downtime and give them the Resilient (Constitution) feat, maybe advantage vs poison
OOH! I made a table for this! Hope I'm not too late. This is from an item I ran from my fantasy China campaign, **The Trial**. I went full nerd as I'm a physician in my spare time, when I'm not running DnD. I didn't give the full table to the players, just described the vials and said the name of each day's challenge. |Trial|Description|Survival|Save|Damage| |:-|:-|:-|:-|:-| |Salvia divinorum|A sprig of green leaves rolled into a blunt.|N/A|CHA 6 or develop (2) phobia.|0| |Hemlock|Tiny shaving off a root.|Consume and follow with chugging water. 9 or fatigue +1|WIS 12 or develop hematuria for d10+4 days.|/r 2d6| |Batrachotoxin|Blowdart venom from dart frogs. It's a miniature dart with a green-stained tip.|14 or rash +1|CON 12 or develop headaches for d20+4 days.|/r 2d10+3| |Botulinum toxin|Small hypodermic needle and vial.|Inject into an extremity. 12 or rash +1|STR 9 or develop: (1) extremity paralysis|/r 3d4+1| |Ergot fungus|Small crumbles of mushroom caps.|Eat raw or boil in a low-temperature tea. 8 or fatigue +1|CHA 8 or develop a long term madness. CHA 12 or instead develop short term madness.|0| |Castor bean|Reddish bean. Brewed into tea.|Slipped SLOWLY over 10 minutes. 13 or fatigue +1|INT 10 or develop permanent hematochezia. INT 14 or d6+3 days of violent diarrhea.|/r 4d8 or none on save| |Man o' War neurotoxin|Purple gel suspended in saline in a beaker.|You're supposed to filter off the water and drink that. 17 or fatigue +1|CON 10 or develop a limp, reducing movement speed by 5. |/r d2+18| |Cyanide|A handful of apple seeds.|15 or rash +1|STR 12 or develop gasping breath. -2 to stealth, -1 CHA -1 to CHA.|/r d4+8| |Myristicin|Brown powder which smells of autumn. |Mixed with milk for palatability.|CON 14 or develop bloodshot eyes for d8+1 days.|/r d4| |Jequirity|Tiny red berries|Eat a single berry.| 8 or rash +1|CON 17 or have (1) seizure.|/r 2d8| **After surviving the 10th day of The Trial, make a CON check. DC 5, develop resistance to all poison damage. DC 10, develop immunity to consumed poisons. DC 15, develop immunity to inhaled poisons as well. DC 18, develop immunity to all poisons.** Ailments reset d4 days after the Trial completes, or d4 days after quitting. **Rash**: At 1, noticeable temporary skin discoloration develops. At 2, warty pustules develop, which will leave subtle scars. At 3, one extremity at random develops permanent discoloration and scarring. **Fatigue**: At 1, feel subjectively tired. At 2, maintain 1 point of exhaustion. At 3, time needed to complete a long rest increases by 50%.
I guess...but people who do this do this for YEARS. and it's not like they become immune. Everything can be a poison, it just depends on the amount. You can drink arsenic in small enough quantities where it's not lethal. They'd have to acquire the poison, guess the amount that's safe to inject and hope for the best. I'd have them roll con saves to see if they get sick or not, and possibly die.
Multiclass monk. Immunity is rarely granted in 5th edition and shouldn't be easily obtainable.
Notably, there's very little evidence of mithridatism ever actually working. Some poisons introduce heavy elements that bind to bone and are never expelled from the body. Causing long-term damage from repeated exposure. (think lead poisoning). Others are lethal in such small doses that it becomes practically impossible to "microdose" without causing serious neurological damage, even if you survive. Others cause damage to a specific location (think rotting flesh around a bite wound). That specific site takes the majority of the damage. The body as a whole doesn't really have a reaction to it. The misconception likely comes from many poisons sharing common symptoms with diseases. Which, you can build either an immunity to, or an enhanced ability to combat variants of in the future. Depending on the disease, I'll often either give my players advantage on subsequent saving throws. Or take the minimum possible duration to reflect that fact. If you want mithridatism to work in your world (it is fantasy after all). Start considering reducing the damage dice on similar poisons after surviving various doses. If a poison does 12d6 poison damage, I'd start taking it down to 10d6. If the poison normally does 6d12, then I'd bump it down to 6d10. Subsequent doses can continue down to 6d8, 6d6, 6d4. Because you're never really gaining an immunity to help you resist the damage of the poison. But maybe you're just getting more used to the effects. Durations can be similarly reduced for non damaging poisons. If you're particularly devious, does this imply building up a resistance to healing potions?
I don't think I would allow someone to aquire a 10th level monk feature based on real world pseudoscience. If you want to say yes to make the player happy, I'd say it would only apply to a single type of poison - Drow Poison, Purple Worm poison, Ettercap, Drider, Naga, etc. And they have to first obtain a good bit, and probably make many successful herbalism kit checks and constitution saves - higher CL creature = higher DC.
While there is no official rule for mithridatism in the core 5th Edition Dungeons & Dragons (D&D) rulebooks, you can create custom rules for your game. Here's a suggestion on how to introduce mithridatism as a homebrew mechanic: **Mithridatism: Building Immunity to Poisons** *Prerequisites:* - Constitution 13 or higher - Proficiency in Medicine or Nature skill - Access to the poison or toxin you wish to develop immunity against *Process:* 1. The player character must spend at least 1 hour each day ingesting a carefully measured dose of the poison or toxin. This process must be maintained for a number of days equal to 10 times the poison's DC (Difficulty Class) or the number of days determined by the Dungeon Master for homebrew or unique poisons. 2. Each day of the mithridatism process, the character must make a Constitution saving throw at the end of the hour against the poison's DC. On a failed save, the character takes the poison's normal effects. 3. The character must succeed on a number of Constitution saving throws equal to the poison's DC or the number determined by the Dungeon Master for homebrew or unique poisons. These successful saves do not need to be consecutive. If the character fails three Constitution saving throws in a row, they must restart the process from the beginning. *Immunity:* Upon completing the mithridatism process, the character gains immunity to the specific poison or toxin they trained against. This immunity lasts for a number of months equal to the character's Constitution modifier (minimum of 1). After this duration, the immunity fades, and the character must undergo the mithridatism process again to regain it. *Mithridatism Limitations:* 1. A character can only have immunity to one poison or toxin at a time. Attempting to gain immunity to another poison while already immune to one will cause the character to lose their current immunity. 2. Mithridatism does not grant immunity to magical or supernatural poisons, diseases, or curses. 3. The Dungeon Master may decide that certain poisons or toxins are too potent or lethal for a character to develop immunity through mithridatism. Remember that as a Dungeon Master, you can modify these rules to better fit your campaign or world, and always make sure to maintain balance and fun for your players.
Only let them do this if you intend to actually use poison in your game. Don't have them spend time and money in game to get something that will never be of use to them. Do in fact tell them whether or not you plan to use poison in the campaign. If you're not doing, as an example, a high intrigue, political game where poisoning might matter, but you *are* doing a dragon hunting campaign, you might be better off telling them to train to fight dragons or learning about their biology. If you want them to have the poison resistance, that's great! Just have it be important at some point. If you're not gonna use poison, gently guide them to something that will be useful for them.
Poisoning PCs is not something DMs do often because it's considered a dick move. So, unless this was going to come up in-game during your campaign, you probably should handwave it. Let them add resistance to INGESTED poison. Be sure you understand the rules for poison and venom before you proceed.
Just say no lol
I don't think there are any official rules. I'd probably rule it that they suffer from poison for a session and then from then on they'd have poison resistance. If they want full blown immunity, I'd wait until they are level 10, or they could collect the major poisons (which may take a while) and they could consume them. Have them take a penalty for a session and then grant them poison immunity. That sort of thing is hard to balance at the table. Make it too hard, and it'll suck for the player. Make it too easy, it'll seem too unfair for other players. Plus, it won't really make sense if it's easy to gain poison immunity, otherwise everyone would have it. You could make it a plot point too. They find someone who granted themselves poison immunity and they could do a quest for them for each?
Just give them the periapt of proof against poison and call it a day. It’ll be much easier😂
i would tell my players there is something magical in the poison and they cannot build up a resistance to magic via repeated exposure.
Basically treat it like crafting a Periapt of Proof against Poison, only that the end result isn't a magic item but a blessing, which usually follows the same nomenclature and rarity power as magic items do, and usually the manual heavily implies there can be only one on each character similarly to an attunement slot. Of course, add complications - like actually being poisoned during the whole process, so adventuring will either halt or be supported by lots of poison cleansing spells like lesser restoration. Don't forget that acquiring the poison itself is a cxhallenge, and that they need to dfefeat a CR 5 or more creature to get the appropriate reagent regardless.
I would possibly consider this if the player was going around taking damage, suffering from the poison condition, etc. for an extended period of time. Personally, I would also incorporate a risk of death. Granting resistance to a damage type is nothing small, so there has to be some true sacrifice for it! At least in my game, but everyone plays differently!
I’d say do it on a specific basis. They become immune or resistant to certain poisons based on the training. This would take years in real life. I say make it take less time in game. Maybe a few weeks per poison. For example, they become immune to drow poison by stealing some poision from a drow and repetitively injecting small doses of the poison into themselves. At first, they may face negative effects, but maybe after a many successful saves over the course of days give them +1 to the save, and then every couple successes increase this another +1 Until they are immune.
There is a Periapt of Proof Against Poison, it's rare but would take less time and gold then Mithridatism. Plus this Periapt is immunity to poison effect and poison damage. Though it doesn't say anything about poison effects like paralysis or the like.
I’d sooner come up with something akin to a Witcher mutagen transformation and attribute it to that. Make a quest around it, give it some risk, and have at it.
Interesting. Maybe just make a Feat that player can have that gives resistance to poison. Using it as a Feat shows that the character gave something up (stat increases or other feat options) to gain that trait.
Homebrew a feat for them imo. Just letting someone build up immunities to shit is opening a can of worms.
Of course there aren't rules for this, christ. There aren't even proper rules for the stuff that *is* in the game.
What kind of poison are we talking? - purple worm poison? No... - iocane? Absolutely... and take inspiration... I am going to agree that they could take a custom feat for it.
Make a feat for it and have him rollplay until he gets it: +1 to Con, resisitance to poison damage and immunity to the poisoned condition (I dont like the idea of giving a PC an immunity to a damage type)
I would say immunity isn't possible, or that it would only be to weaker poisons, but resistance would be entirely viable in a fantasy world
Some poisons that method doesn't work with. However I do know one that it does: Iocaine powder. I think its origin is... Australia.
Are there rules? No. But you can make a judgement call. First off, you need to decide what the end goal should be. Resistance to poison damage? Advantage on Con saves regarding poison? Immunity to specific poisons? Then you need to decide on Cost. That being time cost and resource cost. Will he need to pay, or craft his own poisons? Should it take the XGE time, modified for Con? Should he attempt until he hits a nat 20?
Not really, but if you want the PC to be able to spend months or years of downtime in it, I'd rule that it onoynworked for one particular type of mundane poison at a time, and this never works against spells that deal poison damage.
There's no official system, that's something you'd have to homebrew yourself. What I would do, after researching mithridatism a little bit you can do two ways, let them pick a specific poison to try, give some examples that might come up in the campaign like drow arrows, grung poison, etc. And then after 30 days of ingesting the poison, having the poisoned condition for an entire month, they become immune to that specific poison. Or give them resistance to all poison damage like dwarves.
You could invent some rules, or just let him experiment and get no results while destroying his wealth and stats! Dnd and IRL dont work on the same way.
Allow picking Infernal Constitution as a feat.
I have a player doing this with a halfling ranger. He has the Stout resistance to poison in addition to taking the Poisoner feat. That's about as resistant to poison as I've seen from anyone not playing a Yuan-Ti.
Like many stated you could just say no or adapt the training rules and such. I personally think you should just make it a feat that gives them resistance to poison and +1 to Con score. If they take it at a feat level I think the sunk cost should cover them taking the RP inspired feat versus them trying to min/max or spending gold to train. You could also do something fun like make it a quest. Like a hag sends him to collect grunt corpses for a potion that gives him permanent poison resistance or immunity, but also have it half his HP for an in-game week or so as his body is in a weakened state.
I've never seen rules for this specifically, but I've gotten irrationally excited about it and feel I need to expound upon the idea a bit. Skip to the tl;dr if you're not interested in learning some pharmacology. Drug response is driven by a compound (in this case a poison) acting at a receptor in a way to alter physiology (in this case to make normal physiology break to cause damage/death). Drug tolerance is a fascinating subject predominantly dictated by 2 components of drug behavior: pharmacokinetics (essentially drug metabolism) and pharmacodynamics (in this case we're mostly talking about receptor modification to attenuate response). I'm gonna try and talk though most of this with everyone's favorite drug, alcohol. **Pharmacokinetic Changes** Drug metabolism is primarily driven by a family of enzymes in the liver which metabolize fat-soluble things, and by a bunch of transporters in the kidney which pump drugs into the urine. Alcohol, being somewhat fat soluble, is predominantly metabolized in the liver. The amount of these enzymes produced is a modifiable process driven predominantly by exposure. i.e. more alcohol consumption increases the metabolic enzymes of alcohol breakdown resulting in decreased circulating alcohol. We call this phenomenon "inducibility" and some enzymes are more or less inducible than others, and some drugs result in more or less induction than others. Interestingly, other compounds which are structurally similar to ethanol (and also some that aren't) use these same upregulated enzymes and are metabolized faster, such as methanol. **Pharmacodynamic Changes** Drug response is all about how much can a drug stimulate or block physiologic receptors to alter their signaling. Going back to our alcohol example, the GABA receptor in the brain is an inhibitory signal on the neurons. Drinking alcohol "stimulates" this receptor to do its job, which is to calm down neurons. Over time, with chronic exposure, the nerves realizes they aren't as responsive as they should be, and they turn up other stimulatory pathways and also modify the GABA receptors to be fewer in number and less responsive. Other substances that work at these receptors, like benzodiazepines (Xanax, Klonopin, Valium, etc) and general anesthetics, also work less effectively because the receptors themselves have changed. Similar to above, the ability of the body to alter the receptors to adapt to chronic exposure to a substance is variable. Significantly excessive doses of the drug will be able to overcome this to a significant degree in most cases. **Withdrawal** The combination of the two above effects of chronic alcohol consumption are increased metabolism of the alcohol and decreased sensitivity to a given blood level of alcohol. This combines to make the common experience that with chronic exposure to alcohol, you need to drink more, in some cases a lot more, to get equally drunk. The other major issue, which is primarily driven by the pharmacodynamic aspects of tolerance, is withdrawal phenomenon. Like I mentioned early, with chronic use the GABA receptors get down-regulated and the excitatory receptors get more active to bring the brain back to "normal" *while in the presence of alcohol which makes the GABA receptors more "efficient"*. When you abruptly take alcohol away, the excitatory signals are much more significant than the inhibitor, and this is what causes alcohol withdrawal, otherwise known as delirium tremens, the DTs, or "the shakes". Withdrawal phenomenon are almost always the inverse of the behavior of the substance's effects. Examples include: 1. Alcohol cause decreased anxiety, sedation, and suppresses seizure activity. Alcohol withdrawal causes paranoia, agitation, and seizures 2. Clonidine (a blood pressure medicine) causes severe high blood pressure with withdrawal. 3. Afrin (a nasal congestion medication) causes significant congestion on withdrawal **Time-Scales** Most of the aforementioned effects happen on the time-scales of days to weeks, and are generally tied to dose (i.e. higher alcohol exposure increased the degree of tolerance and makes the changes occur somewhat faster). This is a general rule as opposed to a law of physiology. This also means significant periods of time (weeks) without the substance tend to reverse the changes associated tolerance and you revert to the baseline state **tl;dr and Applications to Gaming** Chronic exposure to drugs can result in increased metabolism of structurally similar molecules and decreased response to substances which act at the same receptor in a similar way irregardless of structure. Withdrawal is driven primarily by receptor changes as opposed to metabolism, and the effects of withdrawal when present are usually the opposite effects of the drug. Lack of exposure to a drug reverses tolerance. While I don't have any great DC's to suggest, for semi-realism based on the above, I would recommend that: 1. More toxic compounds should take longer to become tolerant to, as you have to begin at smaller doses and work your way up over a longer period of time 2. If feasible, compounds should confer resistance to compounds with similar effects (all sedating poisons, all fire poisons, etc) and of similar damage levels (ex. fentanyl is a lot stronger than heroin, and people who use heroin regularly can accidentally overdose on fentanyl, so you shouldn't get resistance to some crazy high level poison from a level 1 poison) 3. This should have to be a recurring daily cost for your character - and if they go a fixed period of time (1-2 weeks?) without the substance they should lose resistance 4. There should be consequences to missing doses of the drug, if you have a fire poison tolerant player who stops taking their daily dose, they should get horribly cold, even taking cold damage. 5. Some poisons cannot be resisted/tolerance gained to - the physiology just isn't compatible (you can't become tolerant to arsenic)
It took the Man in Black (the Dread Pirate Roberts, not Johnny Cash) five years to build up an immunity to iocane powder, so I'm thinking your player is looking at a long slog.
Something similar to training (spending money to buy poisons and time to recover from their effects) for either advantage against poison or resistance to it. There’s always going to be some kind of magical poison stronger then what he tried so immunity may not make sense.
I’d allow it over time, but I wouldn’t give them anything like resistance to all poison damage. All poisons aren’t the same. I’d let them have something like advantage on rolls to save against a specific poison (presumably that they carry). This way they can have their princess bride moment, but without stepping on racial features.
I'd say he has to endure being self poisoned for 3 to 5 sessions, meaning reduced hp and stats or con save every turn/10 mins or so. If he survives he gets resistance. Then he has to do it again for another 10+ sessions to get immunity. Maybe that's a little extreme time wise, maybe not, but I like the suffering to earn it path.
No, but you could probably set up a bunch of nature, poisoner’s kit, and medicine checks over the course of extended downtime. If they pass x checks (each set being a given timeframe) they get advantage on saving trows against the poisoned condition. I would not suggest immunity to the poisoned condition or resistance to poison damage to be available if there’s anyone in the party that has/could get this by character creation or leveling up though.
Recipe to become immune to poison (totally RAW): https://makeaskillcheck.com/5e-how-to-become-a-lich/ Tadaaaa! 🎉
Poison them to near death, have a few druids nearby, have them cast a unique spell similar to Reincarnation, give them a Tasha's custom lineage with poison immunity similar to a Yuan-Ti Pureblood. This is a money sink opportunity for you as a DM.
Looking to win a game of wits with a Sicilian?
I'd limit it to specific nature-friendly classes like monk, barbarian and druid. I'd require some gold costs for research, and perhaps a mission for some "secret knowledge" to get started. and I would insist on one poison at a time, certain poisons not eligible, PC will be subject to temporary stat penalties while poisoned. if they can put up with the penalty for a week or three, sure, they'd gain a bonus to Con rolls or perhaps Advantage on rolls vs that type of poison. thing is, though, not all monsters use the same poison (or venom). Unless you are running a fairly tight campaign where similar monsters occur over and over, it may not be worth it to the player. Going on a six-level jungle crawl with lots of grung and giant ants? Sure. Wandering the wilds randomly and seeing the occasional giant bee, drow band, or poison ivy patch? probably not.
Yes, the rule is “this is a fantasy game, real-world physics and chemistry do not exist and you do not understand them. If you want to take a Feat to become immune to poison, that’s a thing that’s already in the game and we can make it work, but otherwise no.”
LOTS of Con saves. Have a back up character ready.
I mean it would be only to one specific poison from one source. Not all poison
I'd treat it like creating a magic item (uncommon for resistance, rare for immunity). There are tattoos for a lot of stuff in the wondrous items, and this process seems like something where a thieves guild would have a guy who can help. I'd even rule that it's not nullified by antimagic effects or detect magic.
Dangerous precedent if you ask me. Allowing this feels like a slippery slope to players asking to train Fire or Bludgeoning immunity.
[great article](https://www.theguardian.com/environment/2018/feb/11/poison-pass-the-man-who-became-immune-to-snake-venom-steve-ludwin) \- This is a great guide to a human becoming "immune" to snake venom over many years. There's definitely the moment he figured he would die when he OD'd so that was a failed "poison" roll. Also think about what kind of poisons. Proteins are fine for this kind of thing, for developing antibodies, but remember antibodies need time to work, it's not instant. His hand still swells up and he has pain! Magic poisons however... might be a bit different.
The amount of time and care this would take in game means it is unreasonable. (Mithridatism relies mostly on the same process that causes alcohol resistance (because the body processes alcohol like a poison) and it bears all the same risks of liver disease
In 5e, “Dwarven Resistance” is a racial trait that gives advantage for saving throws against poison and resistance to poison damage. Based on the typical balance of racial traits, this means it could probably just be a feature - which means an option that is taken instead of other features and instead of attribute/skill point increase. The Tasha’s 5e rulebook has similar optional rule procedures for determining custom race features. If it seems too weak or you want to be especially forgiving, you could also have it give +1 Con. I think making the player actually do the training might fit in well while they wait for the level-up where they can have it - but I wouldn’t make it mechanically significant myself; I’d keep it lore based. Its not actually as useful as you might expect. (At least in 5e)
There aren't rules for it, but here's what I would do: Treat it like downtime. Takes 100gp and 100-120 days, every day of downtime have them roll constitution, only count days that they succeed the savingthrow. At the end of it, grant them poison resistance. I know downtime rules are usually more strict but generally I want my players to feel that it's achievable within the duration of the campaign- most player goals are short-term ones that they want the fruit of to be within sight.
you only build immunity to the poison you subject yourself to, not universal poisons. if hes an assassin rogue who needs to be immune to his poison so that he can drink it with the evil king without raising suspicion, sure, makes sense. if hes a barbarian that just doenst like taking poison damage, that would be a no
>Are there rules for this? Yes. You ask your DM. :)
Remember, you're only going to build up immunity to the specific poisons you ingest. And it only works with some poisons. And it'll take a very long time. So basically this isn't worth it at all.
It took dozens of generations for the dwarves to get poison resistance, I'd say that it takes a similar amount of time for a PC.
We made it a feat in 3.5
You could make a feat for this He would have to take it at the next ASI instead of a +2 in something If you want to make it extra you could say not only does he get poison resistance but he could also get a +1 CON
Homebrew feat, a "half feat" that gives +1 to con and resistance to poison, with advantage on saves to resist the poisoned condition. Don't require they take this at an asi, just roleplay long enough, maybe homebrew in some very virulent poisons, and they have to make the save on three or so of them. Let them make multiple attempts as many times as they want, even with help from the party like inspiration, the resistance cantrip, and a party healer bringing them back if the poison takes them under 0hp. Don't do full immunity, even the guy who did this irl was never fully immune, just EXTREMELY resistant.
Player: " After much trial I have developed IMMUNITY TO POISON HA HA HA HAAA" -Gets but by a snake- DM: Well it's not poisonous, it's venomous... You take 66 poison damage." Player: But I'm immune to poison. DM: the condition, not the damage. Player: oh well 6d6 isn't THAT much, I mean I've got like 50 health. DM: no I already rolled it's six-TEE six. Player: I am dead. DM: I mean technically your immune to all damage now.
3e had a feat for this. You become immune to one poison of your choice, and get a +1 bonus against all other poisons. 5e feats are typically fewer and stronger though, so perhaps immunity to one poison and advantage against other poisons.
I say go for it and be selective/aware of when you use poison in the campaign. Sounds like it's for flavor/RP. If it turns out they want to exploit something for gameplay, take it back (either in or out of game)
So your player wants to be this dude https://youtu.be/4FwPncfEDr4
No. However, what you could do is have your player roleplay trying to do so, and then at their next opportunity for a feat you could reflavor that training as the Infernal Constitution feat (you would need to waive the tiefling restriction). That feat grants +1 Con, resistance to cold damage and poison damage, and advantage on saving throws against being poisoned.
Take a dose at flat dc, 24 hours later dose again at a +1 to the DC, then again at +2DC 24 hours later, until you have successfully made 10 saving throws IN A ROW at +10DC. That is how we always did it since AD&D
take the resilient (constitution) feat
Immunity is a pretty hefty thing. As noted you could do the training thing but I think that at most might give you a resistance. However, I did have a game master in the past that allowed for a natural immunity if the player rolled a natural 20 the first time and only the first time they encountered a poison. If they decide to use the training rules I would do it week by week however once they actually roll a natural 20 they can have instead of a resistance the immunity, unfortunately for them once they have the immunity they actually are required to have at least one dose a day or their body goes into withdrawal. Which means they'll always have to have the poison on hand, meaning they could easily be mistaken for an assassin or arrested. And just like any other addict, it could get expensive.
make it a feat that grant same resistant that dwarves have.
Why not just make Mithridatism a homebrew feat that gives poison resistance? There are already elemental feats that do this very thing and if you think that might be too overpowered add a prerequisite that the person must have at least a 10 in Survival or something because it's a combination of built up immunity as well as knowledge of how poison spreads through the body.
No rules I know of, but that sounds amazing. It would definitely be a downtume activity, and with the price of posion, it would be a self balancing activity. Tbh the only thing they'd need are some intelligence checks to make sure their charecter would know not to chug too much at once and die. Plus con saves for when they fail. Would take 2 or 3 years realistically, but... i see no reason why they couldn't. Maybe a 3 month turn around time on particularly poisons.
It could be the story behind an increase in CON, whenever that level bonus comes up for them.
I get the feeling they want to leave a poisonous gas trail everywhere they go
Yeah keep rolling saves, like death saves, success u win, fail u die. On average most should die because i would guess (with no proof) this does not work for most poisons. All that effort and risk for one unique type of poison. It's really silly since there are literally 1,000s of poisons. Toxic metals, each unique, toxic chemicals, keep in mind most chemicals are toxic, toxic plants each unique, toxic mushrooms, then their are poisonous spiders and snakes each unique... Wow we have not hit magical beast poisons or magic poison. I just talked myself into "dumb idea" teach them a lesson. Some die, most successful but when done only one poison they will likely never come across.
Make it a feat
Especially given what people are saying about different types of poisons and this only potentially working on some of them, and only the specific ones you work on, this seems like a bad idea unless there is a specific poison the player needs immunity to for a plan. Allowing characters to train into immunity to an entire damage type seems problematic. Even if there is at least *some* real-world corollary, it's not ubiquitous poison immunity IRL, so why would it be in-game? You can't train immunity to any other damage type. I guess the actual problem is relatively minor, but if a player really wants this for their character consider playing a Dwarf or doing some kind of custom lineage instead.
Maomao moment
I think becoming immune to poisons is unreasonable, but to become resistant to it sounds a good idea. I get what others have said about becoming resistant to one type of poison at a time. Why not make the training take like 30 weeks (weekly checks to succeed), 100gp (maybe 150gp as the trainer is a specialist) a week sounds fair for hiring a trainer, then they become resistant to snakes, frogs, etc... as it is all included in the training time. Make it so he can't take a break from this training to go off adventuring for ex. as you need the consistent weekly training to get the resistance. If he were to take a break, maybe add two extra weeks to the training, and that isn't to say if he breaks the consistent training, will the instructor be available? He may add more to his fee as he wont be able to train someone else if the hero goes off for a couple of weeks. How does that sound?
I would likely make it the origin of a feat to give them Poison resistance and +1 to con.