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U.S. Forest Service

Ergot: The Psychoactive Fungus that Changed History

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Since humans first began cultivating cereal grains such as wheat, rye, barley, and oats, they have been susceptible to ergot (Claviceps purpurea) poisoning. This fungus has devastated crops and European societies for many centuries.

Ergot-infested grass seed heads with a U.S. dime for size comparison. Ergot-infested grass seed heads. Photo courtesy Forestry Images.

Most commonly attacking rye, ergot infects and replaces the cereal grain with a dark fungal body called a “sclerotium.” When made into bread or otherwise ingested (e.g. barley beer), it causes ergotism, also known as “St. Anthony’s Fire” or “Devil’s curse.” Convulsions, muscle spasms, vomiting, hallucinations, and a gangrenous pain where the victim’s limbs, fingers, toes, and nose were “eaten up by the holy fire that blackened like charcoal” characterize ergot poisoning. Victims often lost parts of their extremities or entire limbs due to blood vessel constriction associated with gangrenous ergotism.

Julius Caesar lost legions of soldiers to ergot poisoning during his campaigns in Gaul. Severe ergot epidemics in France between 900 AD and 1300 AD killed between 20,000 to 50,000 people, leaving the nation susceptible to invasions that eventually toppled this Holy Roman kingdom into what became two nations, France and Germany.

The ergot fungus contains a number of highly poisonous and psychoactive alkaloids, including lysergic acid (LSD), which was synthesized from the ergot fungus in 1938 by chemist, Albert Hoffmann.

Ergot poisoning is a proposed explanation of bewitchment. Most historians today believe that the witchcraft trials that led to thousands of deaths and burnings at the stake in Europe during the Dark Ages were likely related to outbreaks of ergot poisonings. The unfortunate victims of the Salem witch trials of 1692 also exhibited symptoms of ergot poisonings. Ergotism is rare today due to careful screening of cereal grains.

St. Anthony with a victim of ergotism. St. Anthony with a victim of ergotism.

Victims of ergotism. Victims of ergotism. Pieter Bruegel painting, Louvre.