History Main / AcquiredPoisonImmunity

This can be TruthInTelevision, or not, depending on the poison in question.

For some (chiefly organic) poisons, the body produces antibodies to clear them from the system; so, with repeated exposure to small amounts, you can build up a level of circulating antibody that grants immunity to a typical dose. In the past ages, [[ScienceMarchesOn the few metallic poisons]] known were rare and expensive; therefore most poisons were plant-based alkaloids. However, there are plenty of other poisons (including nearly all heavy metals to which modern civilians and industrial workers are exposed, such as compounds of lead, radium, mercury and cadmium) that ''don't'' [[JustForFun/TelevisionIsTryingToKillUs get cleared from the system and simply build up in your tissues until you reach a lethal dose]].

The official term for this 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.]]

** PlayedForLaughs with [[PoisonousPerson Magellan]], whose Devil Fruit powers allow him to manipulate and create all kinds of poisons; this naturally made him immune to poisons himself, meaning he enjoys eating poisoned meals, but doing so leaves him stuck on the toilet for ten hours a day.
** Less for laughs and more for awesome after the TimeSkip, when Luffy's clash with Magellan gives him immunity to a ''crapload'' of poisons. As if he hadn't [[TookALevelInBadass taken enough levels in badass]] already... Though even then, his antibodies still have limits; a strong enough poison (as in, one that would cause instant death in a normal person) can still make him extremely sick.

* One (SFW) ''Webcomic/{{Oglaf}}'' comic has a very experienced food taster [[http://www.oglaf.com/naturalcauses boasting that he's immune to pretty much everything by now]] to his latest client, who then keels over after one bite of the meal he'd just tasted.

** The heroine gets a rather high poison resistance (and Corrosion resistance, too) from being forced to hunt for prey in a dungeon where every creature is poisonous to various degrees.

See also and closely related to RemovedAchillesHeel, which is when a character gradually gains immunity to an inherent weakness by repeatedly exposing themselves to it.

*** The 5th edition gives us the Artificier (Alemchemist subclass) that can become resistant to both 'Acid' and posion.

* An inadvertent version in ''Series/IClaudius''. The wife of a Roman official is drugging his wine so she can have an affair with Serjanus while he's asleep. Serjanus convinces her they have to MurderTheHypotenuse instead, as he'll eventually become resistant to the drug.

** In ''Series/StargateSG1'', a single shot from a Zat'nik'tel will typically cause extreme pain and/or unconsciousness in subjects. However, it seems that years of exposure to hits from this kind of weapon is enough to build up a tolerance. In later seasons, we routinely see team-members who've been shot with a Zat suffer only mild discomfort and quickly shrug it off, while those who've ''never'' been Zatted before get consistently knocked out. This ends up being a plot point in an episode, where O'Neill has to run to the stargate in order to activate it and force the local EnergyBeings away, allowing the rest of the team to flee. He uses zat shots to temporarily make his ionized body repel the creatures, but the effect wears off after a minute or so. He can't zat himself again, as a second zat shot within a certain time frame is fatal. Luckily, Teal'c shows up just in time and zats ''the ground'' next to O'Neill to the same effect. Wonder why no-one thought of that one before.

* In ''Fanfic/{{Origins}}'', a ''Franchise/MassEffect''[=/=]''Franchise/StarWars''[[spoiler:[=/=]''[=Borderlands=]''[=/=]''[=Halo=]'']] MassiveMultiplayerCrossover, Samantha Shepard has to ''turn this off'' in order to get drunk since she's now more [[Franchise/StarWars machine than woman]]. Mordin Solis even has to adjust the power in her cybernetic legs to let her dance!

* in ''Literature/TheHungerGames'' short story ''Secrets'', a companion piece to "Fanfic/TheVictorsProject" it's mentioned that using this trope was the only thing that kept Luster Lancaster( leader of District One's career victors in the authors previous fanfics) from being killed by one of his own victors (who was prostituted by Snow at Luster's suggestion) several times during the fifth decade of the games.

---> '''Haast:''' "It was risky, but I was cautious. When I started in 1948, a doctor said he wouldn't give me a nickel for me living two years. Well, I'm still here, but the doctor died of a coronary."

* The entire Agriche family in ''Lightnovel/TheWayToProtectTheFemaleLeadsOlderBrother'' practices this due to their rather [[ChronicBackstabbingDisorder unorthodox]] [[TheSpartanWay way]] of raising children. Taken UpToEleven by Roxana, who consumes so much poison (albeit it has less to do with acquiring immunity and more with feeding her [[TheSwarm butterflies]]) she eventually becomes a PoisonousPerson.

* ''Series/ForeverKnight''. Dr. Natalie Lambert tries to wean Nick Knight off his vampirism (which she thinks is mostly psychological) by encouraging him to eat small amounts of food, take garlic pills and use a sunbed. In the past just trying to touch a cross caused Nick's hand to burst into flame, whereas now he only gets a minor burn. This proves useful when he's able to ward off his sire [=LaCroix=] by holding a cross; even though it should effect Nick just as much, [=LaCroix=] breaks and flees before he does.

* ''Series/ForeverKnight''. Natalie tries to wean Nick off his vampirism (which she thinks is mostly psychological) by encouraging him to eat small amounts of food, take garlic pills and use a sunbed. In the past just trying to touch a cross caused his hand to burst into flame, whereas now he only gets a minor burn. This proves useful when he's able to ward off [=LaCroix=] by holding a cross; even though it should effect Nick just as much, [=LaCroix=] breaks and flees before he does.

** Harley Quinn is immune to Poison Ivy's poisons because of all the, uh... time they spent together. In the animated series, this is {{Handwave}}d by having Ivy just give her a vaccine against them.

-> ''"Mithridatism, it's called. Isn't that a funny name? The process of eating poison to build up immunity. So long as I don't die from it, I'll be harder to kill."''

Here's a typical scenario: The hero has finally appeared at his confrontation with the BigBad, who's seated at his big table, just about to take his evening meal. "There's no reason to be uncivil," the villain says. [[NoMisterBondIExpectYouToDine Would the hero like some wine]]? The hero takes a drink and immediately starts choking. The villain laughs - that fool, the hero, should have known that the villain would poison the wine with the dreaded juice of the [[NamesToRunAwayFromReallyFast Ultramurder]] fruit!

* In ''VideoGame/TheLegendOfZeldaBreathOfTheWild'', the [[FishPeople Zora]] are portrayed as being especially vulnerable to [[ShockAndAwe electricity]], which is inconvenient because Shock Arrows are needed to incapacitate the [[HumongousMecha Divine Beast Vah Ruta]] that has been causing havoc for the Lanayru Province. King Dorephan and Prince Sidon decide to seek help from [[HumansAreAverage Hylians]], who lack said vulnerability, but one Zora named Seggin instead tries to develop an immunity to electricity by repeatedly touching a Shock Arrow. He is apparently making some process, as it's mentioned that he can hold it far longer than any other Zora, but it's still excuciatingly painful.

* In ''VideoGame/MassEffect2'', failure to realize that without constant supervision, a sedated Shepard won't stay that way for long, ends up foiling [[spoiler:the [[BrainwashedAndCrazy Indoctrinated]] Alliance agents]] in ''The Arrival''. One medical report in ''The Arrival'' even mentions their frustration that it was necessary to ''increase'' every round of sedatives administered because Shepard's system simply grew immune to the previous dose, given only ''four'' hours earlier.
** Probably justified by the same cybernetics that allows them to survive drinking [[GargleBlaster ryncol]].
* In ''VideoGame/MegaManBattleNetwork'', delibarately ignoring the rules of the Navi Customizer results in [=MegaMan=] getting random bugs that impede his abilities in battle. However, in the [[VideoGame/MegaManBattleNetwork3WhiteAndBlue third game]], persisting through enough battles with these bugs will unlock the [=BugStyle=] Change, which comes with [=BugStop=], allowing [=MegaMan=] to use the Customizer without worrying over bugs.

-->-- '''Jude Duarte''', ''Literature/TheFolkOfTheAir : The Cruel Prince''