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Finger-Licking Poison

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Poisons in detective novels are one of the great romances in fiction. Writers of the genre are always looking for new ways to administer the deadly stuff, which gives us this trope: a murder method wherein poison is unwittingly self-administered when the victim licks an object coated in the poison.

The object could be anything, although the more innocuous, the better. One popular method is to coat the pages of a book in poison so that when the victim licks their finger to turn the page, the poison is passed to them. This is somewhat dated since people don't lick their literature much anymore, but it may be justified by saying the pages were stuck together or from an old, delicate book.

Other seemingly innocent lickable objects, such as stamps or envelopes, are also popular.

Most often a mystery trope, considering the murder angle. Modern examples are probably inspired by the novel/film The Name of the Rose, although one early example is from the Arabian Nights.

Related to, but separate from, Poisoned Weapons and Drugged Lipstick. The murderer may use a Perfect Poison to do the job. Not to be confused with a Fingertip Drug Analysis, though less-subtle examples may rely on the victim trying one.


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    Anime & Manga 
  • Case Closed:
    • In one chapter, a man was murdered via poison applied to the temperature control of a cooking range on which a pot of water was boiling, after which he counted money and licked the poison from his fingers.
    • One of the movies had a woman murdered in a similar way. her make-up artist put the poison in her make-up, and then gave her normal chocolates on an airplane trip. The woman pinched her nose to pop her ears, getting the poison on her fingers, and then ate a chocolate and licked her fingers, ingesting the poison.
    • Another example: a musician is murdered by poison applied on the inside of his jacket sleeve and asked to perform a song that required him to throw off the jacket and take a pose where the poison would transfer to his hand. The food, all non-poisoned, were things like sushi and nigiri and there were no eating utensils.
    • Another man was poisoned via a poisoned wet napkin while eating sushi.
    • And YET ANOTHER was poisoned because his murderer put poison on the spot on the lazy susan between two dishes that the victim was allergic to, and so he kept getting poison on his fingers every time he saw said dishes.
    • A man who disliked sour things was nevertheless poisoned by a lemon wedge in his drink because, as part of a marketing gimmick, he had eaten a miraculin berry and was unable to taste the sourness.
    • Even detectives aren't immune to this trope! He died biting his nails, not realizing that his partner had betrayed him and poisoned everyone's cup handles except for her own.

    Comic Books 

    Film — Live-Action 
  • In the 2010 vigilante film Boy Wonder, Sean Donovan writes a letter to the criminal who killed his mother, saying he forgives him but he must know if his father hired him to commit the crime. So the criminal won't incriminate himself, Sean tells him to send back the enclosed self-addressed envelope with a red stamp if his father is innocent, or a black stamp if guilty. The criminal licks the stamp and dies on the floor of his cell. It was the red stamp, but Sean had already killed his father thinking he was guilty.
  • The Internecine Project ended with the murderer receiving a hand-written notebook from one of his victims. On the last page, it said "I arranged for this to be sent to you after I am dead, and the pages have been soaked in poison that is absorbed through the skin".
  • In A Jolly Bad Fellow, Bowles-Otterly murders Dr. Hughes by coating the tip of his pencil in poison, as Hughes habitually licks the tip of his pencil before writing.
  • In the Awful British Sex Comedy The Naked Detective, this trope was inverted by having it be the way the murder method was identified, rather than committed. The detective had been leaning against the window frame while reading the decedent's will, licked his fingers to turn the page, and immediately spat at the awful taste...and realised that the dead guy's antacid pills had been left on the same window earlier while his germophobic son was spraying bug repellent everywhere, inadvertently poisoning them.

  • In The Accursed Kings, Countess Mahaut of Artois poisons the newborn king by having him put her poison-coated finger in his mouth as she holds him, making this a literal Finger-Licking Poison.
  • Older Than Print: An Arabian Nights tale The Tale of the Vizier and the Sage Duban, wherein the Duban, sentenced to execution by a treacherous king, gives him a book with orders not to read it until after his head has been cut off. After that's done, the head comes back to life and instructs the king to turn three pages with his left hand. When the king turns the pages (naturally, licking his finger along the way) and finds nothing written there, the Duban essentially tells him the pages were poisoned and if the Duban had to go, he was taking the king with him. Moment of Awesome for a severed head. (Unfortunately, this makes the vizier who caused the execution a Karma Houdini, as he didn't touch the book and sure as hell wouldn't after seeing what happened to his king.)
  • In Robin Hobb's Assassin's Apprentice, one of Fitz-Chivalry's assassination ploys was to poison the cutlery instead of the food.
  • This technique is mentioned in Bridge of Birds, with the added element that the books in question were pornographic.
  • In Discworld stamp-collecting, the original Assassins' Guild 3p stamp (the Thrupenny Dreadful), is very rare, at least gummed. The in-universe reason for this is that they were recalled due to unsubstantiated rumours that the Guild was using it to fulfill contracts. In the novel Feet of Clay, this is one of the theories as to how Vetinari got poisoned, in an obvious shoutout to The Name of the Rose. He's mentioned turning pages thusly, although it turns out to be a Red Herring:
    Every so often he consulted the leather-bound journal, licking his fingers delicately to turn the thin pages.
  • Joe Pickett: In In Plain Sight, J.W. Keely murders a prisoner by smuggling him a can of chewing tobacco laced with cyanide. He hopes that the prison guard who probed the tobacco with his finger doesn't lick his fingers afterwards.
  • During the Mallorean series, Sadi kills a man by coating the man's soup spoon with poison.
  • In the Marcus Didius Falco tale Venus in Copper, when the landlord Hortensius Novus is murdered with poison it turns out that all the suspects independently tried to murder him—his own family with a poisoned cake, his business rival with poisoned spices to be added to the wine—but the actual murderer was his fiance, who poisoned the plate the cakes were served on, knowing that gluttonous Novus would lick the plate clean once the meal was done.
  • The Mummy Monster Game: In book 1, this is used as the answer to the challenge for the first arm of Osiris — identifying the murder weapon that killed a young princess. By poisoning the victim's eyeliner and then spilling it, the killer ensured the victim would lick their finger to wet the dried eyeliner, then lick it a second time to make it usable again, thus being poisoned by it.
  • In Murder and Mendelssohn, a conductor who habitually licks his finger before turning the pages of his score is poisoned when the killer coats the top of his score with arsenic.
  • The Name of the Rose: In an attempt to keep Aristotle's Poetics hidden, an evil monk poisons the page corners so anyone who reads it will die before they can tell others about it.
  • Classic example: in Alexandre Dumas' La Reine Margot (AKA Marguerite de Valois), a poisoned book on hunting is used in an attempt on King Henry of Navarre's life, but the plan backfires as the King of France, an avid hunter, sees the book first and reads it with disastrous results. Earlier in the same novel, an even more devious plan to poison Henry via his paramour's lipstick is employed but thwarted by the would-be poisoner who couldn't murder said paramour in cold blood.
  • While it isn't poison, per se, in Red Seas Under Red Skies, Locke and Jean use this as a way to cheat at an uncheatable casino. They're playing cards against a pair of women, one of whom is known to eat chocolates and lick her fingers as a part of her mental game to throw off her opponents. So they dust their suit linings with a powerful sleeping drug so they can keep coating the cards with it. This works especially well since the game also requires that whoever loses a particular hand must down a shot of liquor, with the losing team being the one that has one of its teammates pass out.
  • In Guy N. Smith's apocryphal Sherlock Holmes story "The Case of the Sporting Squire", Royston Morgan (aka "Morgan the Poisoner"), knowing his wife is in the habit of licking her fingers each time she turns a page, kills her by adhering strychnine to the pages of Little Dorrit. She dies alone in a locked room, as he hoped, and the local doctor passes the death off as tetanus, but neither Holmes nor Watson are so easily fooled.note 
  • A Song of Ice and Fire: twice, with the same method. First the prologue of A Feast for Crows: The Alchemist (Jaqen H'ghar's new personality) pays Pate, a novice in the Citadel with a poisoned coin. Pate bites the coin, then the dust. Second, Arya's first sanctioned killing in Dance: she deliberately botches a cutpursery to replace one of the coins of a ship owner with a poisoned one. The owner then pays a greedy insurer with said coin. The insurer also has a habit of biting the coins....
  • The Thinking Machine: In "My First Experience with the Great Logician", the narrator accidentally poisons himself by smoking a cigar he stored in a jacket pocket where, several months earlier, he had carried a packet of insecticidal powder. Some of the powder had leaked and coated the tip of the cigar.
  • The Three Widows, by Ellery Queen had a victim being slowly poisoned even though everything she ate and drank was carefully screened beforehand. It turned out the would-be killer was her doctor and the poison was on the thermometer with which he took her temperature each day.

    Live-Action TV 
  • In one episode of Benson, a person with a habit of sucking on the earpiece of his reading glasses was killed by poison placed on the earpiece.
  • In the Criminal Minds episode "Poison," the team discovers that groups of people who had been slipped LSD had ingested it by licking bank envelopes whose seals were coated in the drug. Later in the same episode, the UnSub tries to poison a group of people with botulism via the same method.
  • The pilot of Crossbones has Tom Lowe using this in an attempt to assassinate the pirate Blackbeard. It almost works, but Lowe is forced to reverse the effect when he discovers discord among Blackbeard's underlings and needs to keep him alive to better investigate it.
  • CSI-verse:
    • CSI: During the course of an attempted murder, the apparent victim spilled ricin on her pen and then killed herself by biting the end of it. This isn't actually possible, as while injected ricin kills in very small doses, a human body can survive ingesting nearly a whole gram of it.
    • CSI: NY
      • In "Grand Master", a woman is killed via poisoned toenail polish, worn by the young woman working as the "table" at a restaurant serving Body Sushi. The young woman was the victim's former personal assistant, fired after refusing her boss's sexual advances and unable to find better work than the body sushi job. On discovering her former PA's new job, the victim took to specifically requesting her table in order to continue harassing her, and particularly enjoyed sucking on the young woman's toes.
      • In "Page Turner", the killer coats the pages of a book in thallium to poison his victims.
  • Death in Paradise:
    • In "Damned If You Do...", the Victim of the Week is poisoned by a lethal dose of poison being placed on the end of his pen through a scratch pad before he retires to write a speech. The killer then poisons the dinner being eaten by everyone, including themself, with a milder dose in an attempt to make it appear he died from food poisoning.
    • In "One for the Road", the killer gives the Victim of the Week an envelope with a poisoned seal, knowing that the victim will lick the envelope, seal it, and place it in her bag. Then, after she dies, the killer doses her glass with poison to make it look like she had drunk it.
    • In "Steamy Confessions", the Victim of the Week is a professor with the habit of chewing on the arms of his glasses when thinking. The murderer poisons him by coating the arms of his glasses with arsenic and then swaps the glasses for the professor's spare set so there is no obvious source of poison.
  • Ellery Queen: The murder method in "The Adventure of Caesar's Last Sleep".
  • Father Brown:
    • In "The Time Machine", one victim was killed by having strychnine placed in the bowl of his pipe.
    • In "The Wrath of Baron Samdi", a musician is murdered when the killer coats the reed of his saxophone in poison. The killer later dusts Father Brown's toothbrush with the same poison.
  • In the Jonathan Creek episode "The House Of Monkeys" the victim was sent a request for a signed copy of his book. The murderer included a stamped addressed envelope to send the book in... stamped, addressed, and poisoned with a psychotropic drug on the flap you lick.
  • In an old Perry Mason episode, it turns out the murder weapon was poison on a brooch and a dress with no pockets. The murderer was the dress designer and the victim was the model picked to show off the dress in question. The dress was designed to wrap around the wearer in a complicated way that required both hands to accomplish, and then be pinned closed with the brooch. Since the dress had no pockets, of course the model would put the brooch in her mouth while tying the dress and got a lethal dose of the poison. But it misfired -someone else tried the dress on first. The murderer tried to cover up the method by putting more poison into the bottle of champagne used to toast the success of the fashion show, but of course Perry saw through that one.
  • In the Red Dwarf trilogy "Back in the Red", Rimmer discovers that the rest of the Dwarfers were put in a psychotropic simulation (to see if they act guilty of the crime they're accused of when everything goes their way and they think nobody's looking) ever since they licked some envelopes at the beginning of their arrest. Rimmer then has to break them out before they reveal that they gave him classified information so he could get a promotion. Rimmer licked an envelope as part of the bureaucracy of promotion, and he's in the simulator too. He blackmailed the wrong people.
  • There was a Remington Steele episode where the poison was in the glue on some envelopes Steele and Laura were expected to lick.
  • Port Charles an enemy of Scott's puts poison in the glue of some envelopes to try and get him. Aside from sickening Scott, there's a very tense scene where his daughter Serena almost licks one of them.
  • In Seinfeld, George's fiancee Susan is accidentally poisoned by the cheap glue on the wedding invitation envelopes because George was too stingy to pay for better ones (and too lazy to seal any invitations himself). And Susan herself for some reason didn't use a sponge rather than lick the envelopes herself—-poison or not, those seals taste terrible.
  • Whodunnit? (UK): In "Death at the Top", the Victim of the Week, who has an Oral Fixation, is murdered when the killer poisons the tip of his pen, which he compulsively chews on during a board meeting.

    Tabletop Games 
  • In the first book of the Grimtooth's Traps series by Flying Buffalo had an 'additional trap', to 'punish' players who read the book. On the trap page, Grimtooth claimed that the book pages had been liberally coated with a deadly neurotoxin absorbed through the skin ... with two blackened fingerprint outlines right where a normal reader would hold the book when reading.
  • In the Pathfinder adventure path Curse of the Crimson Throne, the King of Korvosa is killed this way, setting the entire plot in motion. The poison was placed on playing cards, and the king is a habitual nail-biter.

  • In The Crucifer of Blood, St. Claire is murdered when the killer places a poison dart in the mouthpiece of his opium pipe. When he inhales, he sucks in the dart and stabs himself in the throat.
  • In The Duchess of Malfi, the Cardinal disposes of his mistress Julia by using a poisoned Bible.

    Video Games 
  • A poisoned letter stamp in Apollo Justice: Ace Attorney. Also upgraded to poisoned nail polish, because the intended victim, a young girl named Vera Misham, had a tendency to bite her nails a lot.
  • Finger-licking isn't explicitly mentioned, but in Assassin's Creed II, Agostino Barbarigo dies after receiving several poisoned letters from the Assassins.
  • In Aviary Attorney, luxury chocolates with a custom wolfsbane-derived filling are so poisonous that a character who eats the wrapping which has traces of chocolate on it is hospitalized.
  • A Game at Dinner, an in-game short story in some Elder Scrolls games, has Helseth implying to his assembled dinner guests that he put poison on the cutlery of someone he knows has been spying on him. It turns out to be a subversion, however, as Helseth was Bluffing The Spy, and the real poison is the antidote he offers to the spy if they confess.

    Western Animation 
  • A variant appears in the old TV show Jacob Two-Two, where a bad guy puts into motion a plot to brainwash people into buying his shoddy newspaper via this method. He fails, as the titular character and his friends don't lick their fingers while reading and are able to figure out his scam.

    Real Life 
  • While not highly toxic by itself, Dimethyl Sulfoxide (DMSO) has the property of being quickly and easily absorbed through skin contact, allowing easy contact absorption of whatever else happens to be mixed with it. This allows a deadly but hard-to-deliver poison to be easily absorbed through the skin. It is regularly used as a solvent in industry and scientific research, so it's quite easy to get hold of too.