What does ergot mean?
Ergot is a parasitic fungus, Claviceps purpurea, that attacks rye and other cereal grains, replacing individual kernels with dark, horn-shaped structures containing powerful alkaloids. When humans or livestock eat flour or fodder contaminated with these growths, the result can be ergotism, an illness marked by convulsions, gangrene, and hallucinations — historically known as St Anthony's Fire. Outbreaks of ergot poisoning swept medieval and early modern Europe, and some historians have linked such contamination to episodes once blamed on witchcraft. Beyond its sinister reputation, ergot has a constructive side: its alkaloids yielded medicines used to control bleeding and induce labor, and research into its chemistry contributed to the synthesis of lysergic acid diethylamide (LSD). The word also names a small horny bump on the back of a horse's fetlock, though this sense is confined largely to veterinary contexts. Ergot thus bridges botany, medicine, history, and folklore, making it a striking example of how a single organism has shaped human affairs.
A parasitic fungus of rye and other cereals whose toxic sclerotia contaminate grain and can cause ergotism in people and animals that eat them.
"Wet harvest conditions allowed ergot to spread through much of the season's rye crop."
Often used attributively, as in 'ergot poisoning' or 'ergot alkaloids'.
(Veterinary anatomy) A small horny lump situated at the back of the fetlock of a horse's leg.
"The groom cleaned dirt from around each ergot before bandaging the horse's leg."
Restricted to veterinary and equestrian usage.
(Pharmacology) A dried preparation or extract of ergot alkaloids used medicinally, especially to contract the uterus.
"Midwives once administered doses of ergot to control postpartum hemorrhage."
Now uncommon, as purified alkaloid drugs have largely replaced crude ergot preparations.
Regular plural. Often uncountable when referring to the fungus or contaminating material generally.
"Dark ergots were scattered among the otherwise healthy rye kernels."
The notorious 'witchcraft' hallucinations behind events like the Salem trials may have been fueled by bread made from ergot-contaminated rye — and decades later, chemists used this same fungus to synthesize LSD.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ergot
Ergot entered English from French in the early seventeenth century, where ergot originally meant the spur of a bird such as a cockerel; the name was applied to the fungus because its dark, claw-shaped growths resemble such spurs. The French word itself is thought to derive from Old French, possibly related to argot. English retains both the botanical sense and, via the same image, the equine sense referring to the small spur-like growth on a horse's fetlock.
Related word forms
How ergot is actually used
Primarily a technical term found in agricultural, medical, historical, and scientific writing rather than everyday conversation. In historical contexts it often carries connotations of epidemic poisoning and superstition. The equine anatomical sense is restricted to veterinary and equestrian usage.
Easily confused with ergot
Argot means the specialized slang or jargon of a particular group, while ergot is a parasitic fungus of cereal grains.