What Is Ergot?

The European Food Safety Authority (EFSA) says ergot alkaloids are produced by several fungi, and that in Europe Claviceps purpurea is the most widespread Claviceps species. EFSA based its 2012 risk assessment on the main ergot alkaloids found in that fungus, namely ergometrine, ergotamine, ergosine, ergocristine, ergocryptine and ergocornine and their related epimers, and set a group acute reference dose of 1 microgram per kilogram of body weight and a group tolerable daily intake of 0.6 micrograms per kilogram of body weight per day.

The EU limits ergot in grain foods. A 2024 EFSA opinion notes that Commission Regulation (EU) 2023/915 introduced maximum levels of ergot sclerotia for certain unprocessed cereals, and maximum levels for ergot alkaloids in milling products of barley, wheat, spelt, oats and rye, and in wheat gluten.

A 2025 review in Metabolites says that in the Middle Ages, epidemics of St. Anthony's Fire caused convulsions, hallucinations and gangrene in communities that ate ergot-contaminated rye. A 1974 review in Annals of Surgery says both gangrenous and convulsive symptoms are seen in naturally occurring ergotism from eating fungus infected rye, and that the symptoms appear to result from restricted blood flow caused by ergot-induced spasm of blood vessels. The 2025 review notes that ergotamine and ergometrine are among the most significant ergot compounds because of their established medical use.