Some people have very intense allergic reactions, there's a few that can even be fatal if medical attention is not administered immediately. Which can be convenient for murderers.
You see, unlike most poisons, it's very easy to pass off an allergic reaction as an accident, and a disturbing number of common fatal allergens can be bought at a supermarket. Additionally, frequently one can admit giving the victim the allergen, denying awareness of the allergy.
A subtrope of Plot Allergy. For straightforward cases of suicide by allergy go to Self-Induced Allergic Reaction. Often a case of Tampering with Food and Drink. See Weaksauce Weakness for when the allergy has a supernatural cause but is still a ridiculously mundane item. As a Death Trope, spoilers are unmarked.
Examples:
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Anime & Manga
- Case Closed:
- In a filler case, Rich Bitch Hiromi Yamazaki is completely terrified of bees due to being allergic to their sting (and she almost died when stung by one as a little girl)... and the person who killed her is smart enough to actually use bees as one of their "killer weapons". More exactly, they caused her to panic at the sight of some bees released on the highest floor of her Big Fancy House, then covered the door handle in honey so there would be more bees there, and when Hiromi leaned on a wooden rail... the rail was "broken", causing her to fall to her death.
- In the "Chinatown Déjà Vu in the Rain" case, the murderer exploited the murdered's egg allergy to deal the latter with a Clean Food, Poisoned Fork. They (and some colleagues) go to a Chinese restaurant (where food is put on a lazy Susan and served family-style), order two dishes with eggs (and a few that don't), and arranged to have two egg dishes to put next to each other—and put poison on the underside of the lazy Susan right between the two egg dishes. Since the victim will obviously push it away...
Comic Books
- In Superman (2023), Lex flicks a peeled acorn into the mouth of an inmate with a severe peanut allergy who was badmouthing Superman and talking up Batman. Superman confronts Lex over this, as the inmate nearly died from anaphylactic shock, though Lex mutters that acorns technically don't have the allergen that leads to anaphylaxis, meaning that the man's reaction was psychosomatic.
Fan Works
- In The Loud House fanfic Clown Scene Investigation
, a bratty little boy named Roy injects salmon oil into a slice of birthday cake belonging to his classmate Collin, which Collin is allergic to because he was angry that he wasn't invited.
- Total Drama Comeback Series: Courtney has a massive grudge against Harold that finally comes to a head during the E is for Eating challenge in Chapter 28. She gets ahold of his list of allergies and spikes his soup with gummi slugs, which nearly kills him, so he'll be deemed unfit to continue the competition and be voted off.
- In With Pearl and Ruby Glowing, Ratigan assaulted Noah and secretly put red meat into his food beforehand, which would have triggered his alpha-gal syndrome and silenced him. This only didn't work because Noah lost his keys and alerted his parents, who got him to the hospital for a rape kit before he went into shock.
Film — Live-Action
- Black Widow (1987). A woman (Theresa Russell) knows her husband is allergic to penicillin. She murders him by putting some in his toothpaste, causing him to suffer a fatal allergic reaction that appears to be a heart attack.
- Bottoms: The Huntington football team attempts to murder Jeff by spraying the football field with pineapple juice, which he's deathly allergic to.
- Glass Onion: Duke is deathly allergic to pineapple; after he tries to blackmail Miles over Andi's murder, Miles discreetly swaps Duke's drink with one that contains pineapple juice.
- Horrible Bosses: attempted by the protagonists when they learn Bad Boss Harken has a severe peanut allergy. They plot to put peanuts in his bathroom products to kill him, but the plan goes off the rails when they see Harken commit a murder and have to escape.
- The sequel to Jack Frost (1997) has both Sam and Jack Frost sharing the same banana allergy after a blood transfusion. Sam defeats Jack and his children with bananas.
- Mrs. Doubtfire: Daniel, disguised as Mrs. Doubtfire, spikes Stu Dunmeyer's food with peppers he knows him to be allergic to as a juvenile prank. But when Stu begins choking, Daniel realizes he crossed a line, and performs the Heimlich maneuver on him, saving him. Daniel apologizes for the peppers, and Stu, for his part, seems forgiving.
- Parasite: The housekeeper Moon-gwang is deathly allergic to peaches. The Kim family exploits this to get her fired by inducing an allergic reaction and framing it as tuberculosis. Later, when Moon-gwang and her husband Geun-sae are threatening to expose the Kims as scam artists, Ki-jeong gets the upper hand by running to get some peaches from the fridge and rubbing them in Moon-gwang's face.
- Peter Rabbit: At one point, Peter and his gang slingshot blackberries at Mr. McGregor to distract and incapacitate him. At one point, a blackberry lands in McGregor's mouth, resulting in him having to give himself an Epi-Pen while the rabbits run off.
- Tucker & Dale vs. Evil: Jerkass Chad is allergic to chamomile. Dale, who remembers everything and is much smarter than he gives himself credit for, happens to come across a box of chamomile tea while he's fighting Chad...
Literature
- In The Cupcake Club: Peace, Love and Cupcakes: The cupcake club is warned not to put cinnamon into the cupcakes because Meredith is allergic to it. Kylie is tired of Meredith bullying her, so she gets revenge by putting cinnamon in the cupcakes anyway. She soon regrets it and worries that she's actually killed Meredith.
- The Da Vinci Code: Rémy's peanut allergy is exploited when his boss decides he has outlived his usefulness and sprinkles some peanut dust in his wine.
- In the Diagnosis: Murder book "The Silent Partner", a son donates a kidney to his father, who dies of an allergic reaction to penicillin at the end of the surgery. Turns out the son, who was aware of his father's allergy, intentionally took a humongous dose of penicillin in order to murder his father with the kidney.
- Jaine Austen Mysteries: In The PMS Murder, Marybeth Olsen is killed via someone taking advantage of her peanut allergy.
- Kate Shugak: One victim in A Night Too Dark is killed when her cookie is spiked with peanut oil to induce a fatal allergic reaction.
- In The Many Half-Lived Lives of Sam Sylvester, Billy Clement was murdered by someone who put peanut oil in his popcorn ball. In the present day, the killer tries to do the same thing to Junius Sylvester by adding walnut extract to his "nut-free" coffee cake. Sam finds him gasping for breath on the floor and calls an ambulance.
- In the Monk book "Mr Monk Is Miserable", a flight attendant on Monk and Natalie's plane uses her boyfriend's peanut allergy to kill him upon finding out he is actually married. It backfires on her because she uses her bare hands covered in peanut dust to personally deliver his sandwich when she used tongs for the other food. That alongside her fingerprints on the peanut wrapper are the proof needed to arrest her.
- One of Us is Lying: Supposedly what happened to Simon... that's not quite so. He put peanut oil in his own drink and framed his least favorite people for his murder. Because they hurt his feelings. Drama Queen.
- In Rubbernecker, the killer drops a peanut into Sam Galen's mouth, causing his throat to swell shut. The death isn't viewed as suspicious because the victim had suffered severe brain damage and had pneumonia. When Patrick finds the peanut lodged in the back of the cadaver's throat, he suspects foul play because the victim was on a feeding tube at the time of his death.
- In The Talking Parcel, Ethelred and Penelope accidentally discover that the Cockatrices are terribly allergic to lavender. Later, when the army of Mythologia attacks Cockatrice Castle, the foot soldiers are armed with lavender water pistols.
- In The Vor Game Cavilo's perfume makes Miles' eyes water and causes him to sneeze uncontrollably — and causes her to muse about weaponizing it. Later, Cavilo heavily douses herself with the perfume for a last encounter with Miles before she goes into exile. Miles counters with a pair of nose filters.
Miles: I'm not crying, you bitch, I'm allergic to your goddamn perfume!
Cavilo: Oh, dear. This gives me the most marvelous idea for a gas grenade. - Vera Wong's Unsolicited Advice For Murderers features a bad guy with many allergies who dies of one of them in Vera's tea shop—and it's not exactly intuitive as to how that happened since he was allergic to birds and died of bird dander. Vera has "bird's nest" as a tea ingredient, and the murderer used a stash of that tea to take the victim out.
Live-Action TV
- The Blacklist: Reddington and two warring families are poisoned by an assassin who invented a drug that effectively shuts off a person's immune system for a day, making them allergic to pretty much everything. A glaring case of Artistic License – Medicine as allergic reactions are caused by an overactive immune system.
- The Boys (2019): In season two, Queen Maeve saves Starlight from being strangled by Black Noir by force-feeding him an Almond Joy candy bar, which seems to incapacitate him; Maeve informs Annie afterward that Noir has a tree nut allergy.
- Burn Notice: In "Old Friends", Michael is hunted by a Czech contract killer named Jan Haseck, whom Fiona discovers always eats at either a particular hot dog stand or by ordering room service and supervising the preparation. They work out that Jan is allergic to peanuts, and Mike poisons him by sprinkling crushed peanuts on his hot dog, then steals his Epi-pen and holds it just out of his reach in hopes Jan knows something about the burn notice. All he's able to tell Mike before he passes out is that the CIA isn't protecting him anymore (which he already knew), so Mike administers the antidote and calls Sam to have Jan arrested by the FBI.
- In one episode of Castle, the Victim of the Week is killed by drinking vinegar, with the taste disguised by cranberry juice. He had a medical condition that made him unable to eat or drink anything fermented.
- The Coroner: In "That's the Way to Do It", the unpopular mayor of Lighthaven has her scone spiked with shellfish (to which she is allergic) and her epi-pen and inhaler removed from her handbag. The would-be murderer knows that the allergy won't actually kick in until the mayor engages in vigorous exercise and also knows that she will be meeting up with her lover for an illicit sex session. The killer hopes the murder will be written off as exercise-induced anaphylaxis.
- CSI: Crime Scene Investigation:
- In one episode, a juror tries to invoke this on a fellow juror who was holding up the process, hiding peanut butter in his chili. But it turns out his death was due to a bee sting.
- One man, finding the hired help, a man nicknamed Happy, has been sleeping with his wife, feeds her shellfish so that when she fellates Happy, it will trigger his allergy and send him into anaphylactic shock. This is the first of a string of attempts to kill Happy that night.
- CSI: NY:
- In "YoungBlood," a guy dies of anaphylactic shock when two others prank him by sneaking lobster broth into his soup even though they know he's allergic to shellfish. They thought it would just make him sick, so they follow him when he rushes out of the restaurant, taunting him all the while. When he collapses and dies, they realize they took it way too far and dump his body in a lake in Central Park.
- In "Blacklist," a terminally ill cancer patient takes revenge on his oncologist for stopping his treatment after his insurance ran out. Knowing the doctor is allergic to peanuts, he hacks the order system in a restaurant the man frequents and removes the instructions to omit peanut dressing from his salad. After one bite, the doctor starts choking and has to be rushed to Intensive Care at his own hospital.
- Death in Paradise: In "A Deadly Curse" to dispose of their second victim Daniel Morgan, the killer takes advantage of his severe allergy to insect bites, hiding a kissing bug within his matchbox and draining his EpiPen so it's useless.
- Diagnosis: Murder:
- In "The Murder of Mark Sloan", Vanessa murders Constance by sending her flowers, which Constance is allergic to.
- In "Slam Dunk Dead", Dwayne intentionally put cat fur, which Desmond was allergic to, on Desmond's team uniform. As Dwayne knew, Jesse would perscribe Desmond a medication called tersenadine, which would interact with an antibiotic called clarithromycin, which Dwayne had laced Desmond's health formula with, to kill Desmond. While the trope was used as part of a murder plot, it was merely used to cause enough inconvenience to get the deceased to talk to the team's medical person.
- In "Food Fight", an attempt is made to murder Martin Gaylord by putting some peanut oil on a napkin, since he is allergic to peanuts.
- Doctor Who: Discussed in "The Unicorn and the Wasp", when the Doctor laces the soup with piperine (pepper) in order to try to smoke out the disguised insectoid Vesperform — piperine doubles as an insecticide. No one drinks the soup, so ends up getting subverted.
- Endeavour: In "Prelude" Margaux Quincannon, the lead violinist in the Oxford Concert Orchestra, suddenly chokes to death during a performance. Max concludes she died from a fatal reaction to a nut allergy, but the Thames Valley police struggle to determine how she was killed as she hadn't ingested anything before the performance. Morse eventually figures out the killer ground the nuts into power, then embedded it in the wax that was used to prepare her violin. Thus during the performance as she played the dust came loose and she was unwittingly inhaling it.
- Father Brown: In "The Enigma of Antigonish", as part of their twisted revenge scheme the killer hides tiny pieces of apricot in Captain Peters's lunch knowing he's deathly allergic. Captain Peters nearly chokes to death from the fruit but is thankfully gotten to hospital in time.
- Galavant: In the first season's penultimate episode, Gwynne and Chef make a plan to poison the aristocrats at their banquet. When the time comes, Chef loses his nerve and just serves everyone foods that they are mildly allergic to, inconveniencing them for the night. This gets the two of them thrown into the dungeon.
- In The Glory, the first victim of Dong-eun's revenge plot is the teacher who ignored the bullying she suffered and who also physically abused her. She accomplished it by befriending the teacher's son and revealing her past. Since the son was going to be a teacher himself, his career could be ruined if the scandal would to ever go public. So he murders his father by filling a room with flowers to make him suffer an asthma attack.
- In Killer and Healer, Boss Yu is allergic to crabs and eating its roe could cause an allergic reaction that could kill him. When Zhan Jubai learns about this after suspecting his true identity, he uses this to torture him.
- In Law & Order episode "Born Again", Janet Weston causes the death of her daughter by having the daughter covered with a blanket which carried particles of latex, to which the daughter was allergic.
- Misfits: In the third episode of season 2, Superhoodie tosses a bag of peanuts to the Misfits so that they can use it against the Villain of the Week, who is highly allergic to peanuts.
- In Monk:
- In "Mr. Monk Goes to the Theatre", Hal Duncan gets curtain called for good when he bites into an apple covered in peanut oil, triggering lethal allergies.
- In "Mr. Monk Goes to.the Hospital", Dr. Scott tried to cause a nurse to give Monk tetracycline, which he is allergic to.
- Norsemen: Orm attempts to assassinate the Lawsayer, who is allergic to hornet stings, by unleashing an angry swarm of hornets in his hut. It works about as well as Orm's last murder attempt, he's forced to finish the old man off with his bare hands before he gasps out who did it.
- Oz: Supreme Allah dies when Hill secretly feeds him eggs, which he is deathly allergic to.
- Poker Face: In the episode "Exit Stage Death", murderer Kathleen attempts to trick blackmailer witness Rebecca into eating peanuts, rather than pay her off.
- Tatort: The murder victim in the 2017 episode "Babbeldasch" succumbs due to her allergy to poppy seeds. As the police investigate, it turns out that there was indeed some poppy injected into her food, and she died because someone else kept her emergency set.
- Victorious: In "Tori Gets Stuck", Jade spends the whole episode trying to get Tori out of the way so she can take the lead role in the musical. The first sabotage she tries is to send Tori a bouquet of bush daisies, which she's highly allergic to. Luckily, Trina noticed and warned her before anything could happen.
Video Games
- The Elder Scrolls IV: Oblivion:
- Vincente Valtieri is a vampire who is seriously allergic to garlic note . If you take an Assassination Sidequest against him, you can slip some onto his person to weaken him before you attack.
- Alval Uvani is a Dark Elf with a crippling allergy to honey, and the target of another Assassination Sidequest. If the player character can trick him into drinking a bottle of mead, he'll suffer a paralysis effect that makes him very easy to dispatch.
- Genshin Impact: Oni are known to be horribly allergic to beans, with even the slightest exposure being able to incapacitate them. The Traveler uses this to subdue Arataki Itto in the latter's Story Quest instead of trying to take him head-on in a fight, as he is known to be one of the most powerful Vision bearers in Inazuma.
- In Nancy Drew: Warnings at Waverly Academy, a girl who calls herself the Black Cat has been playing malicious pranks on other girls at her boarding school. A few weeks ago, she slipped tree nuts into Megan Vargas's food, causing a severe allergic reaction. She had to be rushed to the hospital, and afterwards her parents made her come home. Megan, who has been to the hospital because of her allergies many times before, thinks her parents are overreacting and doesn't like missing so much school.
- Not for Broadcast: In the "Live & Spooky" DLC, Patrick is unwilling to hand Holly the tape Marie gave them that would expose his father's misdeeds. Holly collects some dust (which Patrick had mentioned being allergic to during the start) and smacks Patrick with it, stunning him and giving her a window to run off with the tape.
- Resident Evil 4 (Remake): This game's version of Ramon Salazar has an egg allergy, a weakness he did not have in the original game. A single gold egg if thrown at his main body during the fight against Salazar will take away seventy percent of his health on any difficulty making him much easier to defeat in battle.
- Simon the Sorcerer 3D has two puzzles involving this trope:
- In order to clear out a games room, Simon exploits the fact that one of the players has an allergy to anchovies by ordering them a pizza with all toppings including anchovies and extra cheese. The player eats the pizza and gets sick and everyone else abandons the game.
- In order to extort a lawyer with a deathly allergy to bee stings into signing a contract, Simon soaks his clothes in honey then sets a swarm of bees loose on him. The lawyer's allergic reaction triggers and Simon offers him a herbal remedy in exchange for his signature.
- In Shadowrun: Hong Kong one mission involves extracting someone, and one way to get to him is to convince the restaurant staff into serving his bodyguard shellfish - which he is allergic to. Doing so means he only shows up at the end of the mission with a unique portrait showing his face had swollen up and in obvious pain.
- Discussed in Starcraft when it's mentioned in some flavour text that Zerglings are allergic to lemon juice, and it's suggested as a method of trying to repel them. Becomes a Brick Joke in the sequel when the Zerg Evilutionary Biologist will occasionally mutter to himself that he's still trying to find a way to remove that particular weakness.
Webcomics
- In Homestuck, the Courtyard Droll kills Jake English's dream self by force-feeding him peanuts, to which he's allergic, while he's asleep. However, he does so by shoving whole peanuts still in their shells down his throat, so it's possible that Dream Jake simply choked on them before the allergy got him.
Western Animation
- The Adventures of Jimmy Neutron, Boy Genius: In "Ultra Sheen", Jimmy transports himself and Sheen into Sheen's Ultra Lord game where they have to fight Robo-Fiend. While it is easy at first, Carl raises the game level without realizing the danger he is putting his friends in, prompting the two to have to really fight for their lives. Eventually, Sheen manages to match Robo-Fiend in power. That's when he reveals his knowledge of Robo-Fiend's weakness which is that he is lactose intolerant and promptly sprays him with llama milk.
- American Dad!: In "Wiener of Our Discontent", Stan grants Roger the responsibility of carrying the epipen for his shellfish allergy. Roger wastes no time feeding Stan cookies laced with shellfish so he can feel a sense of importance as "the decider" of whether Stan will live or die.
- Arthur: In "Binky Goes Nuts", in a dream Binky Barnes got kidnapped by Dr. Legume who attempts to smear the boy with peanut butter since he has a peanut allergy. Bionic Bunny comes to save Binky from getting exploited from his allergy and ties Dr. Legume and his henchman up their own slice of bread peanut butter.
- Back at the Barnyard: In one episode, Otis cheats at a footrace by putting petunias (which Abby is allergic to) on the track so she'll be slowed down by sneezing.
- In the Fillmore! episode "The Currency of Doubt" the culprits who stole from Toby's locker swapped his lunch of boiled eggs with fake eggs made of cheese. Biting into the fake egg was enough to trigger Toby's lactose intolerance, forcing him to leave the vicinity of his locker, allowing the culprits to freely break in with no one around to see.
- Grossology: The episode "When Allergies Attack" has Lance Boil going on a crime spree using a weapon capable of detecting what it is a target is allergic to and sprays them with a distilled version of it. Abby is seemingly the only person who's immune due to her claim of having no allergies until she eventually discovers hers to be ladybugs, which Boil takes full advantage of. Fortunately, the Grossologists manage to obtain the weapon and use it to defeat Boil by finding his own allergies.
- The Simpsons: Played for laughs in "Please, Homer, Don't Hammer 'Em". When Bart learns of Principal Skinner's peanut allergy, he uses a peanut tied to a stick to publicly force Skinner to humiliate himself; Skinner then learns about Bart's shrimp allergy and duels him with a shrimp tied to a stick. The duel ends in a draw as they both fall into a vat of peanut shrimp and suffer violent reactions.
- Squirrel Boy: In "The Trojan Rabbit", the Johnsons get a new pet rabbit named Archie, who actually wants to rob them. Rodney bests him when he, after learning that Archie has an awful mold allergy, weaponizes one of Andy's moldy gym socks.
- Star Trek: Lower Decks: In the episode "Old Friends, New Planets", Tendi chooses the small scrawny very much not combat ready bird-alien Dr. Migleemo as the USS Cerrito's Champion to fight the trained Orion pirate brute B'Eth as Tendi know's Dr. Migleemo's down will set off B'Eth's allergies. This backfires when he does indeed set of B'Eth allergies... but she passes out on top of him knocking him out completely as she's so much bigger than him.
- Verminious Snaptrap from T.U.F.F. Puppy is the only rat in the world with an allergy that makes him swell up immensely if he eats cheese. His evil plan in "Operation: Happy Birthday" is to rid the world of cheese, claiming if he can't have it, then no one should. Near the end of the episode, Dudley gets Snaptrap to grant him one last request before he drops him and Kitty into his lava pit; they celebrate Kitty's birthday. Dudley then uses Keswick's Flashbaker to make a cake, which Snaptrap eats, not realizing until too late that it's a cheesecake. This makes Snaptrap swell up and hit the controls that not only set Dudley and Kitty free but also capture his henchmen.
- WordGirl: Defied by Chuck, The Evil Sandwich Making Guy, who made sure Word Girl didn't have a peanut allergy before using a peanut butter gun.
