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"Joker Venom" is the name of a poisonous chemical substance used by the Joker. Often considered the Clown Prince of Crime's signature weapon, it causes victims to laugh uncontrollably. Lethal variants of Joker Venom have been known to leave victims with a permanent smile on their face. The Joker himself is immune to the effects of Joker Venom after prolonged exposure to it.



A 1996 Fleer OverPower collectible game card

Joker Venom has a variety of depictions over the years, ranging from liquids to gases. In each form, Joker venom causes its victims to laugh uncontrollably and incapacitate them. The venom's effects also causes the victims' faces to turn into rictus grins through the effects on their muscles. Depending on the variant, Joker Venom can cause either death, render the victim catatonic/comatose, or even cause permanent brain damage. Some variants have also been known to cause disfigurements, such as rendering the victim's skin white, turning their hair green and lips red.

Most versions can only work if the victim is exposed or has the agent ingested, such as being injected with the chemicals or breathing them in. Liquid Joker venom is often absorbed through the victim's pores, though some have been known to work with only foods or drinks. Gaseous Joker venom has can only work if inhaled, though some versions have been known to work if the victim is directly exposed to the agent or bypass gasmasks. Joker's equipment has often been modified to disperse or expose victims to the venom, such as a handheld needle, a joke-flower which sprays it, or bombs that release the agent into the air. Joker Venom has also been known to be split into components, only working when the components or victims are exposed to the necessary components at one time.

Joker Venom's contents is widely disputed. According to a report by S.T.A.R. Labs, Joker Venom contains "a hellish mixture of hydrogen cyanide and Strychnodide (a strychnine derivative)".[1] In one investigation, Batman learned that its signature ingredient was Dubnium/"Hahnium".[2] It is also speculated that this drug contains tetanus toxin (also known as lockjaw). Mixing Joker Venom has often required the Clown Prince of Crime to steal ingredients or even use the facilites at the Ace Chemical Processing Plant. However, on one occasion, Joker was able to mix it from products he'd stolen from the janitor's closet at Arkham Asylum.[3] While Joker has often mixed the agent, other criminals have been shown as capable of mixing Joker Venom independently, such as the Riddler and Punchline.[4][5]

Lethal effects[]

Contact with Joker venom causes uncontrollable spasms of laughter, followed by a painful death. Some have speculated that the venom hyper stimulates the laughter functions of the brain, leaving the victim unable to breathe. It is also possible that this drug contains tetanus toxin (also known as lockjaw). Patients often exhibit a grotesque grinning expression called "Risus Sardonicus" due to spasms of the facial muscles (CN VII). Mortality often follows this clinical presentation. 

Non-lethal effects[]

The venom causes uncontrollable laughter (as if one just heard a very funny joke or saw something that they perceived as hilarious), but instead of dying, their faces are usually pulled into an unusually large grin. Artists often stylize the effects, adding yellowed teeth, bulging eyes, paleness etc. similar to the features of the Joker himself. Prolonged exposure to the non-fatal forms can cause permanent brain damage.

Known Variants[]

According to Tim Drake, there have been over 50 variants of Joker Venom.[6] The following are variants confirmed to have been used by the Joker in the comics:

  • A lethal variant with a timed reaction effects[7]
  • A gas variant which only paralyzed.[7]
  • Joker fish variant - disfigured fish with Joker's signature look, though was implied to be non-lethal by Batman during a toxicology investigation[8]
  • Two-part concoction[8]
  • "Chuckles" - a narcotic created by Maxie Zeus mixing it with Ecstasy[9]
  • Frown-inducing variant - split between chemicals treated on cloths and cleaning solutions[10]
  • Aggression inducing variant[2]


It is commonly believed that the Joker created the Venom before his turn to crime, due to some accounts suggesting his past as a lab technician. One account has suggested that the chemical was once created by Melvin Reipan, a cousin of the Joker who was confinced them agent would make people "ugly".[11] Another, however, suggests that Joker created it himself after stealing both the chemicals and a mixture that created him from Ace Chemical Processing Plant.[12]

The first public use of Joker Venom during his first crime spree, where he would administer it to his victims through a variety of means, including being injected into the victim prior to the announcement or being laced around a set of cards.[7] Joker often made use of the lethal variant prior to the creation of other weapons such as his joy buzzer.

In one scheme to copywrite fish, Joker flooded the Gotham Bay with a variant which disfigured fish with a signature Joker smile. However, he made use of a lethal variant with various forms and once gave a fish laced with it to a cat to murder its owner. With the poisoned Laughing Fish, the venom was injected into the fish then passed along into a cat to attack the target. The variant utilized with the former was implied to be non-lethal by Batman after doing a toxicology screening, as Joker intended to simply get it trademarked. In The Killing Joke, Joker uses a spike worn in his palm (similar to his Joy Buzzer) to administer the drug in a handshake. In Batman: The Man Who Laughs the Joker uses bullets laced with Joker Venom in order to kill another of his selected targets. In Jeph Loeb's and Tim Sale's Catwoman: When in Rome Joker venom is duplicated by the Riddler to blame Catwoman for the murder of a Sicilian Mafia kingpin. It is referred to as Joker Juice by both Catwoman and The Riddler.

In Other Media[]


Batman: The Animated Series[]

Joker venom is used frequently in the animated series, and its spin-offs such as Batman: Mask of the Phantasm. The most popular use of it in the animated series is through a "Very Special Flower" on The Joker's purple suit. In Batman Beyond: Return of the Joker, The Joker used this on an elderly Bruce Wayne after ambushing him at the Batcave. During the series the non-lethal version was more often used, due to the fact this was a children's program. Though the lethal version was occasionally used, with the victims often getting an antidote in time, or in the case of Poison Ivy, simply having no actual effect beyond her laughing it off. Effects of the toxin presented within the show varied from stretching faces into smiles to simply causing uncontrollable laughter until the toxin wore off or an antidote was given.

The Batman[]

Both versions of the venom are used in this series. The non-lethal version is weaponized as a gas and seems to dissipate over time. The gas is called "laughing gas", and puts its victims into a coma. Batman provided an antidote to this laughing gas. However, Joker also has a lethal version which is a liquid. The effects of this venom are the same as the one used in the Joker's first appearance in the comics (a venom which takes 24 hours to kill). In the meantime, the victim slowly has increasing bouts of uncontrollable laughter until they are unable to breathe and die. Batman was once infected with the venom, but was able to create a cure before it was too late. Penguin was infected as well although he was cured offscreen. These two characters are the only ones we eve see infected with the lethal venom. The lethal venom is also explosive, as shown in "The End of the Batman", where Wrath and Scorn fall victims to it. However, it's not used to kill them but instead used to break their minds to prevent them from revealing Batman's identity, and therefore spoil Joker's fun.


The creation of the Joker Venom was covered in the fourth season of the prequel series Gotham. It was invented by Scarecrow on Jerome Valeska's orders, who later used it to drive his brother Jeremiah into madness.

Justice League Action[]

Brchest This section is a stub. You can help the Batman wiki by expanding it.

Joker Venom appears in the show on several occasions..



The Joker uses "Smylex" specifically in gas form, in an attempt to kill everyone at a celebration in the center of Gotham. He also contaminates household products with binary compounds of the chemical, which is only lethal when mixed together the right way.

The Dark Knight[]

Joker Venom does not appear in the film, but Joker's preferred method of murder (carving Glasgow smiles into victims' faces and applying make-up similar to his own) might be a subtle reference. The novelization mentions that Hamlin, a private investigator hired by Maroni and the crime lords to discover his identity, was murdered with a poison that causes him to laugh hysterically to death. It is heavily implied to be derived from Scarecrow's Fear Toxin. Additionally, some have theorized that the gas grenade stuffed in the Gotham National Bank Manager's mouth contained Joker Gas and not harmless smoke.

LEGO DC Comics Superheroes: The Flash[]


Superman, Wonder Woman, Firestorm and Plastic Man uncontrollably laughing after getting infected by Joker Venom

During a vacation in Metropolis, Joker uses his Joker Gas to make the citizens of Metropolis laugh to death. Firestorm and Superman are about to get the Joker, but Joker’s blimp popped behind them, and they get infected by the Joker Gas. After taking down Joker’s Robo-clowns, the villain fakes giving up and tricks Plastic Man and Wonder Woman into having a photo, making the two heroes infected by Joker Gas. Cyborg (who hasn’t been infected by Joker Gas) is still putting his body parts back together after getting electrocuted by Joker’s Joyshocker bomb on the Javelin, watches as the Daily Planet gets jokerfied, saying This does not look good, Joker says that its hilarious making Superman, Wonder Woman, Firestorm and Plastic Man laugh even harder, Joker plans on staying at metropolis forever as his new vacation for eternity. Atom discovers the Joker Gas cure saving the citizens of Metropolis (and the Justice League) from laughing to death, ruining the Joker’s vacation. When stuck in a time loop, after The Flash snatches Joker’s Fun Cannon button, Joker is about to douse him with Joker Gas, but Batman stops him before Joker can do it.

Video Games[]

LEGO Series[]

Joker Gas is often used by the Joker in LEGO Batman: The Videogame, though always in cutscenes. In "The Joker's Return" plotline, he and his gang plan to destroy Gotham City with the gas, releasing it from Gotham Cathedral.

In LEGO Batman 2: DC Super Heroes, Lex Luthor recruits Joker to use his mind-control variant of the toxin to win the presidential election. The gas is spread through a giant Joker robot, though the despiser is eventually taken out by Batman and Superman.

Joker Gas also appears in LEGO DC Super-Villains, where it can be mixed several times by the Joker to bypass security guards and obstacles. To create the toxin, Joker must collect and mix a trumpet, a rubber chicken and a Joker Fish.

Batman: Arkham Series[]

Ark mansDecontamination 2607

Joker Toxin is an obstacle for several areas in the video game Batman: Arkham Asylum.

In Batman: Arkham Asylum, Joker Venom (referred to in the game as "Happy Gas" by the Joker, "Smilex" by the canisters and "Joker Toxin" by others) appears as an obstacle in many areas in the game. In parts of the Asylum, Joker fills rooms with the Joker toxin, which requires Batman to vent them before proceeding. In the later game, Joker attaches some cylinders of the gas to several security controls. If Batman fails to correctly hack them in time, they release the toxin into the air and harm/kill him.

Joker Venom appears briefly in Batman: Arkham Origins, where it is used to kill the Gotham Merchants Bank Manager. Her contorted face is often shown haunting Batman throughout the game.

Background Information and Notes[]


Joker Venom and Red Dust composed of the same material.

  • According to co-creator Bill Finger, Joker Venom was directly inspired by an episode of the Shadow radio serial, The Laughing Corpse, which features a poison with the exact same effects.
  • Joker Venom has had a variety of names depending on the writer. Over the years, these have included: Smilex, Smylex, Laughing Gas, Joker Gas, Happy Gas, Giggle Gas, Joker Juice[4], Laughing Toxin, Laugh-A-loads, Perma-Smile, Smiley Gas, and Joker Toxin.
  • Joker Venom has often been compared to the Red Skull's "dust of death", a chemical which causes the head of its victims to transform into a "red skull". During the crossover story Batman & Captain America, both Joker and Red Skull survived when they attacked each other with their signature poisons, with the latter noting that the two were alike.


  1. DC Technical Manual: S.T.A.R. Labs 1993 Annual Report
  2. 2.0 2.1 Batman (2011-2016) #17
  3. Batman #426
  4. 4.0 4.1 Catwoman: When In Rome
  5. The Joker 80th Anniversary 100-Page Super Spectacular
  6. Detective Comics #880
  7. 7.0 7.1 7.2 Batman #1: "The Joker"
  8. 8.0 8.1 Detective Comics #475
  9. Batman: Cacophony
  10. Batman (2011-2016) #13
  11. Batman: Legends of the Dark Knight #50
  12. Batman: The Man Who Laughs

External links[]