Buttercup: And to think, all that time it was your cup that was poisoned.
The Man in Black: They were both poisoned. I spent the last few years building up an immunity to iocane powder.
Poison has always been a useful and versatile tool for when you want to kill someone. Whether you put it on your weapons, the food someone is eating or even in the very air that someone must breathe, there are all sorts of ways to use it, and that's before we get into some of the more creative things you can do with it, such as forcefully recruiting someone for a job.
There's just one problem: no matter what Perfect Poison you use supplied to you by a Master Poisoner, there's always the issue of actually getting your target to take it. And if they're safely hidden away and cautious about what they eat or drink, that doesn't leave you with a lot of options. One ploy, however, is to consume, (or appear to consume) some of the poisoned substance yourself, thus convincing your target that it's safe for them to eat or drink whatever you've prepared for them.
Naturally this tends to work best if you have Acquired Poison Immunity, a Magic Antidote, or an Improbable Antidote on hand to take in order to negate the poison, otherwise it tends to result in a Mutual Kill. If killing your target is important enough to die for, however, then Taking You with Me might not seem like such a bad outcome.
When someone using this is immune to the poison in question, it also counts as Exploited Immunity. Another way of pulling this off is with two substances that only become poisonous when mixed together. Compare and contrast with the Deliberate Injury Gambit and False Reassurance.
- Nobunaga no Chef: Kennyo serves French macaroons to Oda Nobunaga, and demonstrates that they are harmless when he and his staff begin nibbling on some themselves. However, he then encourages Nobunaga to eat three macaroons at once, whereupon the high concentration of nutmeg sends Nobunaga into overdose and almost results in his death.
- In Ooku, O-Shiga sacrifices her own life in an attempt to kill the sociopathic Harusada by sharing poisoned food with her. She was intending to slowly poison Harusada without killing herself, but was driven to desperate measures when Harusada decided to kill Ienari. Harusada just survives, but is left completely paralysed and forced to helplessly watch all the good people she worked against succeed.
- Ravages of Time: Lu Bu steals a kiss from Diao Chan ( actually assassin Xiao Meng in disguise) and realizes, too late, that her lips had poison on them.
- Gold Tree And Silver Tree demonstrates this trope is Older Than Print. Gold-Tree learns that her wicked mother Silver-Tree is visiting for what she can reasonably conclude will be a third assassination attempt. However, this time, she, her husband, and the woman her husband married when he believed Gold-Tree to be dead are prepared. The two princesses meet Silver-Tree as she arrives, and the second princess explains that it is regional custom for the guest to take first drink, thus compelling Silver-Tree to drink the same potion she intended to give Gold-Tree. From there, the princesses and their prince live Happily Ever After.
- In The Emperor's New Groove, Yzma's plan to poison Kuzco fails because Kronk forgot which cup had the poison, so he had to mix all the drinks together and he and Yzma only pretend to drink with Kuzco. It didn't matter anyway if they had, since Kronk had used extract of llama instead of poison, and only succeeds in turning Kuzco into a llama.
- The Princess Bride features a "battle of wits" between Vizzini and the Man in Black. The Man in Black sets up two goblets of wine, shows Vizzini a rare, odorless, and colorless poison powder then challenges Vizzini to determine which goblet is poisoned. Vizzini does a Look Behind You and then does the Poisoned Chalice Switcheroo, and makes his choice about which goblet to drink. Vizzini then waits for the the Man in Black to drink, and when the Man in Black does so with no hesitation, it leads Vizzini to believe that the Man in Black thought he was drinking from the "safe" cup, which Vizzini now has thanks to the switch, so he drinks too thinking that he has won. The Man in Black had Acquired Poison Immunity and had poisoned both cups, leaving Vizzini Out-Gambitted. (And dead).
- In Red 2 when Bailey is in custody he gets rid of his captors by sliding open the bottom of his shoe to reveal an ampule of nerve gas and a syringe of antidote. He gives himself the antidote and gasses everyone else around.
- In the climax of Airman, Bonvilain attempts this with Queen Isabela and Conor's parents while they're having a toast. However, they suspect what he's up to and refuse to have their drinks, and he's later weakened enough by his own poison for Conor to kill him.
- The Belgariad: A Tolnedran politician killed another by sharing with them a poison that kills the drinker if they get angry.
- Several Agatha Christie novels have this.
- In Peril at End House, Nick eats chocolates she poisoned herself to keep up the ruse that someone is trying to kill her as part of an elaborate plan to make her murder of her cousin Maggie look like an Accidental Murder by someone who wanted Nick dead instead.
- In Death Comes as the End, the murderer deliberately drinks poisoned wine before his brother comes to join him, being sure to only drink enough to make him sick. Because he is known as a man of moderation, while his brother tends towards excess, no one is surprised that he has only consumed a little of the wine and survives, while his brother consumes a lot and dies. And because he was the first to drink the wine, it looks like he was the killer's target and the brother was collateral damage.
- In Sad Cypress, the murderer consumes the same amount of poison as the victim but has an injection of apomorphine ready at hand and is able to throw it all up at time.
- In Curtain, Hercule Poirot uses his own sleeping pills to render another man unconscious, putting them into both his and his victim's cups. As he had been taking these pills for years, he has a degree of immunity to them himself.
- Brought up in 4:50 from Paddington: when the whole family is poisoned and the housekeeper is all right, the latter is suspected at first, until another character points out that any intelligent poisoner would have been careful to pull the gambit. As it turns out, that character, the family doctor, was the real murderer, so there was no self-poisoning after all.
- In the Dashiell Hammett Continental Op short story "Fly Paper" (1929) a woman wants to poison her abusive boyfriend, but is afraid he'll be suspicious if she gives him something without drinking it herself. After reading The Count of Monte Cristo she takes small doses of arsenic (extracted from flypaper) to build up an Acquired Poison Immunity, but instead fatally poisons herself. In discussing the case afterward the detectives reveal that the book is wrong; while some people have a natural resistance to arsenic, it's not possible to build up an immunity through controlled exposure. The poison of choice in The Count of Monte Cristo is in fact Brucine, and is subject to Mithridatism.
- The Professional Killer Achimas from The Death of Achilles recalls one of his hits where he killed an old rich industrialist by spiking the wine both of them drunk with a rare poison that caused cardiac arrest if the victim's heart started beating faster than usual. After finishing the bottle, Achimas told the industrialist that his nephew was planning to kill him, causing an immediate death, then walked home very slowly and carefully to give the poison enough time to denaturate.
- In Dune, Dr. Yueh Wellington put a poison capsule tooth on Duke Leto Atreides's mouth and told him that when he gets captured by the Harkonnens and delivered to Baron Vladimir Harkonnen himself, he must bite the capsule when the Baron goes near him in order to ensure that the poisoned gas would be released. Since they're both aware that Leto would not make out of this alive, Yueh reassures to him that Jessica and Paul are safe and out of the Harkonnens' way. The plan nearly worked except Leto only got to kill the Harkonnen's mentat, Piter de Vries, and several soldiers while the Baron was lucky to step out of the distance.
- In The Hunger Games President Snow attempts this with mixed results, as no antidote is perfect and he suffers from mouth ulcers, giving him a permanent smell of blood.
- In the Lord Peter Wimsey novel Strong Poison, the villain shares a poisoned omelette with the victim after building up a tolerance to arsenic. note
- In Marlfox, Queen Silth is offered wine by her daughter Lantur. After a round of I Know You Know I Know Poisoned Chalice Switcheroo, a panicking Lantur drinks the wine from her own cup and collapses, Silth drains the wine from the remaining cup... and dies, as Lantur reveals the poison was in Silth's cup the entire time.
- Swartt Sixclaw gets rid of a rival warlord by offering him wine and an ornate cup to drink it from, taking a swig from the wineskin first himself to prove it's safe. The warlord has his Giant Mook drink first before drinking, both enjoying the wine. The next morning, the latter two are found dead, and when the captain interrogates Swartt, he drinks the rest of the wine to prove it isn't poisoned (the wine wasn't poisoned, but the cup was).
- This pops up several times in A Song of Ice and Fire:
- At the start of the second book, Stannis' Honest Advisor Cressen, who loves Stannis like a son, attempts to do this to the Ambiguously Evil Sorceress Melisandre, who he feels is leading Stannis astray. He expects this to be a Taking You with Me, however Melisandre is protected by her magic, (and foresaw the event beforehand and gave Cressen a chance to back out) while Cressen dies.
- In a prequel story, a Dragon Rider named Ulf the White turns into The Starscream in the middle of a civil war and opts to try to crown himself king. A knight from the side Ulf was fighting for comes to talk with him bringing poisoned wine, but Ulf suspects something is up and won't drink until the other man does. The knight quaffs a whole glass, after which Ulf drinks too and they both die.
- In Exiled: Clan of the Claw, a Mrem slave tells the ambitious Liskash princess how her seemingly weak Psychic Powers can be used to kill, and talks her into getting herself a Klingon Promotion. He then serves poisoned wine at her coronation dinner, wiping out the Liskash leadership and allowing all the other Mrem to stage a breakout. When the new queen challenges the slave to drink some of the wine himself before she has any, he does so with a smile, knowing that he's buying freedom for his friends.
Mrem: [to dying queen with his last breath] I Die Free. I die for my people. You just die.
- When Captain Sheridan is captured in Babylon 5, he is Denied Food as Punishment for several days to soften him up before an interrogator begins torturing him into a False Confession. During one of the earliest stages of interrogation, the interrogator begins eating a sandwich right in front of the ravenously hungry Sheridan, and offers Sheridan a piece if Sheridan says what the interrogator wants to hear. Sheridan uses some Exact Words to Take a Third Option, and the interrogator appears impressed enough to give Sheridan the food anyway. Sheridan gets paranoid just before eating, until the interrogator points out "You saw me eating it, didn't you?" Sure enough, later in the scene the interrogator reveals that he has Acquired Poison Immunity, and the food makes Sheridan sick.
- Breaking Bad: This is how how Gus defeats the Juarez Cartel in "Salud". Gus brings a rare and expensive bottle of tequila (which is of course poisoned) to the meeting with the heads of the Cartel where they think Gus is going to surrender to them. Don Eladio, who is Properly Paranoid, refuses to drink until after Gus does so. Gus apparently anticipated this, as shortly before the toast he took a pill of some kind and shortly afterward he excuses himself, goes to a bathroom, and tries to vomit up the poison. Gus is still affected by the poison and would have died without prompt medical care, but he fares better than the heads of the Cartel, who drop like flies within minutes.
- Scrubs played this trope for laughs. The Janitor takes a bite of a cake he offered to J.D. to prove that it's not one of his pranks. Unlike most versions, Janitor has no immunity, and the next shot is both of them sitting in the bathroom due to the laxative he put in the cake. J.D. asks, "Who would do this to themselves?!", to which Janitor replies, "Worth It!"
- In The Expanse when their complicity in the Protomolecule scheme is about to be exposed Undersecretary Errinwright and the Martian ambassador share a bottle of scotch that contains a poison tailored specifically to the ambassador's physiology and his death is passed off as suicide.
- Fear Itself: The episode "Eater" contains a variation. The last surviving cop, having been disarmed, wounded and cornered in a closet with no escape route, makes the decision to eat and powder herself in rat poison. Thus when the unstoppable cannibal serial killer-Voodoo sorcerer kills her shortly after by biting her throat out he is poisoned and dies.
- Game of Thrones Season 5 finale, "Mother's Mercy", has Ellaria Sand poisoning Myrcella Baratheon by kissing her on the lips. After getting on board on the ship that is heading back to King's Landing, Myrcella started to nosebleed and slowly collapsed into her father's arms. Meanwhile, Ellaria also had a nosebleed after being affected by the poison but she administered herself with the antidote immediately which was provided by her daughter.
- The Twilight Zone (1959) episode "The Jeopardy Room". A Soviet commissar tricks a defector 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 Versailles, the lover of Fabien Marchal, the king's chief of security, is in reality a spy from the faction who wanted to take down Louis XIV. After making fall him in love, she gives Fabien a "love potion" which both drink before making out, just to see her later vomit it thanks to some ingredients she ate previously that would throw out the poison. Later, Fabien is seen not well, including Incurable Cough of Death and Blood from the Mouth.
- In some versions of Snow White, only half the apple is poisoned, so the queen eats the half that's not poisoned, leaving the poisoned half for Snow White.
- A variation is used in an episode of American Dad!. In that episode it's revealed that Barry acts the way he does because of the pills he takes every day, pills that Stan convinced him to throw away. Off his medication, Barry becomes smarter as well as meaner, manipulative and even talks with a British accent. Things go back to normal after Steve prepares some drinks and dares Barry to guess which one contains a dose of the meds, and leads to Steve revealing to Stan that he spiked both drinks, and consequently Steve acts like Barry until the medication wears off.
- In one episode of Samurai Jack, there's a scientist (presumably working for Aku) who poisons a well in an attempt to kill Jack. Jack seems to realize that something is up at the last second before drinking, but then appears to drink from the well, and afterwards he falls down and seemingly dies. When the scientist goes to check the body, Jack suddenly turns towards him and spits out the poisoned water into the scientist's mouth, and because the scientist inadvertently swallows, it ends up killing him instead.
- Star Wars: The Clone Wars: In 'Dooku Captured', Anakin and Obi-Wan are partying with Hondo's crew of pirates, and are savvy enough to discretely swap drinks with two of the pirates. But then it turns out all the drinks were drugged, and they wake up in a cell at the beginning of the next episode.
- In one episode of The Adventures of Jimmy Neutron: Boy Genius, Jimmy takes his friends to search for a scientists that invites them for dinner, but turns out he added a chemical into the food that would transform them into seaweed golem slaves. When Jimmy points out that he ate it as well, he simply answers that he has an antidote, and proceeds to drink it.