According to this Wikipedia article, death from laughter is a rare form of death, usually resulting from cardiac arrest or asphyxiation, caused by a fit of laughter.
In very specific details:
Death may result from several pathologies that deviate from benign laughter. Infarction of the pons and medulla oblongata in the brain may cause pathological laughter.
Laughter can cause atonia and collapse ("gelastic syncope"), which in turn can cause trauma. See also laughter-induced syncope, cataplexy, and Bezold-Jarisch reflex. Gelastic seizures can be due to focal lesions to the hypothalamus. Depending upon the size of the lesion, the emotional lability may be a sign of an acute condition, and not itself the cause of the fatality. Gelastic syncope has also been associated with the cerebellum.
I remember some times when I laughed so hard I almost fainted due to the excessive physical stress, the sudden expelling of air and the lack of breathing for a few seconds, and I'm sure that you've experienced the same at least once in your life. These hysterical laughter lapses always come with a hard time trying to calm down and an ugly side effect guilt, not for what you laughed at, but for how hard you did it.
People that died laughing -either documented or said-
Going back to the Wikipedia article, there are notable cases of people to have died laughing:
- Cleopatra, the ruler of the old Egypt, said her retainer died from laughter after witnessing her husband's death - not sure if they're talking about Mark Antony. Yet this would be a bogus claim, since her death is quite discussed by several anthropologists as discussed here.
- Zeuxis, a 5th-century BC Greek painter, is said to have died laughing at the humorous way he painted the goddess Aphrodite – after the old woman who commissioned it insisted on modeling for the portrait.
- One ancient account of the death of Chrysippus, the 3rd-century BC Greek Stoic philosopher, tells that he died of laughter after he saw a donkey eating his figs; he told a slave to give the donkey neat wine with which to wash them down, and then, "...having laughed too much, he died" (Diogenes Laertius 7.185).
- In 1410, King Martin of Aragon died from a combination of indigestion and uncontrollable laughter.
- In 1556, Pietro Aretino "is said to have died of suffocation from laughing too much".
- In 1660, Thomas Urquhart, the Scottish aristocrat, polymath and first translator of François Rabelais's writings into English, is said to have died laughing upon hearing that Charles II had taken the throne.
- In 1799, William Cushing, a pauper who lived in the parish of St Andrew's, Norwich, England, died from "a fit of excessive laughter, which lasted five minutes."
- In 1893, farmer Wesley Parsons laughed to death over a joke told in Laurel, Indiana. He laughed for nearly an hour. He then died two hours after the incident.
- On 24 March 1975, Alex Mitchell, from King's Lynn, England, died laughing while watching the "Kung Fu Kapers" episode of The Goodies, featuring a kilt-clad Scotsman with his bagpipes battling a master of the Lancastrian martial art "Eckythump", who was armed with a black pudding. After 25 minutes of continuous laughter, Mitchell finally slumped on the sofa and died from heart failure. His widow later sent The Goodies a letter thanking them for making Mitchell's final moments of life so pleasant. Diagnosis of his granddaughter in 2012 of having the inheritable long QT syndrome (a heart rhythm abnormality) suggests that Mitchell may have died of a cardiac arrest caused by the same condition.
- The 1988 movie comedy A Fish Called Wanda features a scene where actor Michael Palin gets some French fries stuffed up his nose. In 1989, a Danish audiologist named Ole Bentzen found the scene so sidesplittingly funny that his heart rate rose to an estimated 250-500 beats per minute, leading to a fatal heart attack.
There is an extra list with unverified citations about fictional deaths, most of them taking place in famous movies and TV series. Just to mention a few:
- In the computer game Fallout, a gangster named Victor may die from laughter after speaking to a player character whose intelligence statistic is too low.
- Kenny McCormick, a character on South Park, suffers said fate in the fifth-season episode "Scott Tenorman Must Die" while he watched a video of Cartman singing "I'm a Little Piggy" and oinking.
- All the victims of The Joker's "Smilex" gas on the Batman franchise.
- At the end of the film Mary Poppins, Mr. Dawes, Sr. is said to have died laughing after being told a joke.
- In Ice Age: Dawn of the Dinosaurs, the heroes cross a "Chasm of Death" filled with gas fumes that induce uncontrollable laughter, frequently killing those who try to cross the chasm.
- In the Monty Python sketch "The Funniest Joke in the World", the British win the Second World War by translating a lethally funny joke into German and transmitting it to German troops and two Gestapo officers.