History Main / AcquiredPoisonImmunity

** One issue revealed that the title character regularly devises antidotes and methods of controlled exposure to Scarecrow's fear gas. However, every time Scarecrow attacks Batman with gas, he changes the formula afterwards so that immunizing against the previous has no effect. Batman does it [[CrazyPrepared simply on the off chance that Scarecrow didn't change it this one time]]. In ''[[ComicBook/BatmanGrantMorrison Batman RIP]]'', Batman reveals that he is immune to many toxins and poisons, [[ProperlyParanoid and carries antidotes for all the ones he isn't immune to]].

* ''[[https://www.royalroad.com/fiction/72301/1-lifesteal/ 1% Lifesteal]]'': The "Hundred Wet Hells" body tempering technique works by making ''every particle of water in the user's body'' turn against them. The first time Freddy uses it, he immediately passes out, presumably from something in his brain being affected. However, the more the user becomes accustomed to the technique, the more their body becomes resilient to the effects, with the result that they can largely ignore all kinds of pain, disorientation, nausea, etc.

* In ''Literature/AveXiaRemY'' Liu Jin's training under Old Jiang starts with Jiang feeding him a fruit that leaves Jin paralyzed until he is able to use KiManipulation to purge the poison. After several months of learning how to deal with progressively more potent toxins, the next step of his training is a test by the Nine-Headed Snake God that causes his body to constantly produce poison that he needs to neutralize for three years. By the end of this trial Jin is able to shrug off poisons that would kill cultivators vastly above him in PowerLevels and neutralize almost anything that attemps to affect his body.

* ''VideoGames/BaldursGateIII'': Minthara takes small doses of various toxins with her meals to build up an immunity, which can result in an accidental DruggedLipstick if the player is romancing her.

* ''Film/ThePrincessBride'': The Man In Black challenges Vizzini to drink from two cups, one of which has been poisoned with iocaine. After they both drink [[spoiler:and Vizzini dies, the Man in Black reveals that he poisoned both cups because he'd spent the last ten years developing an immunity to iocaine]].

* The main character, Maomao from "Literature/TheApothacaryDiaries" has built up a level of immunity to most poisons due to her frequent experimentations with drugs and poisons, something that comes in handy when she becomes a poison taster.

* ''ComicBook/HarleyQuinn'': In one issue, Harley rapidly throws off an attempt by Dr. Hugo Strange to drug her and explains to him that it's a bit silly to try to poison someone who's had long-term sexual relationships with both the Joker and Ivy.

* ''Series/TheTwilightZone1959'': In "[[Recap/TheTwilightZoneS5E149TheJeopardyRoom The Jeopardy Room]]", the Soviet commissar Vassiloff tricks the defector Major Ivan Kuchenko into drinking wine mixed with a sleep drug by drinking first. He built up an immunity to the drug by repeatedly taking increasing doses over time.

* In ''Literature/RiverOfTeeth'', [[MasterPoisoner Hero]] has acquired a poison immunity by taking small doses of poison with their iced tea each day, though it's never specified which poison in particular it is.

The official term for immunizing oneself to poison this way is Mithridatism, after a king who made use of the effect. It backfired when he was defeated and [[BetterToDieThanBeKilled tried to commit suicide]]; his immunity to poison [[GoneHorriblyRight worked so well]] that he ended up needing to [[ICannotSelfTerminate hire a mercenary]] to [[ImpaledWithExtremePrejudice run him through.]]

* Subverted in ''Manga/{{Bleach}}''. During Mayuri's fight with Szyael, as his bankai's poisonous gases seep over to the injured Uryu and Renji, Uryu initially believes that unlike Renji, he will be safe from the poison, as he was poisoned before in his previous battle with Mayuri. Uryu then shows symptoms of poisoning, and Mayuri mocks the idea that someone could become immune to his poison, saying that it is constantly adapting itself.
** Earlier, during the Bount arc, Soi Fon is poisoned by one of their dolls. While this poison does affect her, she has built up an immunity to her zanpakuto's and several others. If she ever comes across a poison she isn't immune to, she stabs herself with her own poison which eats the strange poison without affecting her.

** AJ's Sandshrew has Acquired Water Immunity. As ground types, Sandshrew are typically weak to water. This one can ''swim''.

* The eponymous heroine of the ''Literature/{{Angelique}}'' novels (set during [[{{UsefulNotes/LouisXIV}} King Louis XIV]]'s reign) survives an assassination attempt when the killers force her to drink a cup of poison. Unbeknownst to them, she had already taken for some years a pill each day, filled with minute amounts of the most common poisons [[TheCavalierYears of that age]]. This got played [[RealityIsUnrealistic realistically]], as despite the acquired tolerance and the fact she throws up just after the assassins leave, [[DoNotTryThisAtHome she still got very sick for the next few days and barely survived]].