/ˈɜːrɡətˌɪzəm/ UR-gət-iz-əm) is the effect of long-term ergot poisoning, traditionally due to the ingestion of the alkaloids produced by the Claviceps purpurea fungus—from the Latin clava "club" or clavus "nail" and -ceps for "head", i.e. the purple club-headed fungus—that infects rye and other cereals, and more recently by the action of a number of ergoline-based drugs.

Chronic exposure to ergot alkaloids has been linked to reproductive issues, such as spontaneous abortions and infertility, due to their action on the pituitary gland.

[citation needed] Dark-purple or black grain kernels, known as ergot bodies, can be identifiable in the heads of cereal or grass just before harvest.

[4] Infested fields must be deep-ploughed; ergot cannot germinate if buried more than one inch (2.5 cm) in soil[citation needed] and therefore will not release its spores into the air.

One of the most notable incidents occurred in 944 AD in France, where ergot poisoning led to widespread hallucinations, gangrene, and convulsions.

Another significant case is associated with the Salem witch trials in 1692, where some historians believe ergotism may have contributed to the symptoms reported by the accusers.

The 12th-century chronicler Geoffroy du Breuil of Vigeois recorded the mysterious outbreaks in the Limousin region of France, where the gangrenous form of ergotism was associated with the local Saint Martial.

Likewise, an outbreak in Paris around 1129 was reported to be cured by the relics of Saint Genevieve, a miracle commemorated in the 26 November "Feast of the Burning Ones".

[6] The blight, named cockspur[7] owing to the appearance of infected grains, was identified and named by Denis Dodart, who reported the relation between ergotized rye and bread poisoning in a letter to the French Royal Academy of Sciences in 1676 (John Ray mentioned ergot for the first time in English the next year).

[8] The outbreak and the diagnostic confusion surrounding it are vividly described in John Grant Fuller's book The Day of St Anthony's Fire.

[9] Ergot sclerotiums were found in the gut of the Grauballe Man, a bog body dated the late 3rd century BC.

[10] When milled, the ergot is reduced to a red powder,[11] obvious in lighter grasses but easy to miss in dark rye flour.

Whenever there is a combination of moist weather, cool temperatures, delayed harvest in lowland crops and rye consumption, an outbreak is possible.

[15] In 1982, historian Mary Matossian raised Caporael's theory in an article in American Scientist, in which she argued that symptoms of "bewitchment" resemble the ones exhibited in those affected by ergot poisoning.

Spanos and Gottlieb also state that most of ergot poisoning's symptoms, like crawling and tingling sensations, vertigo, tinnitus, vomiting, and diarrhea, do not appear in the records of events in Salem.