"Ergot" refers to a disease of many species of cereals and grasses caused by several fungal species in the genus Claviceps. Only the flower of the plant is infected and this is where the fungus develops. Eventually, a survival structure know as a sclerotium would form in the ovary, instead of seed. The sclerotia contain alkaloids, some of which are poisonous to people and livestock. Some alkaloids have medicinal properties.

.Ingestion of toxic alkaloids from the sclerotia of some species of Claviceps can lead to a disease known as ergotism. The most famous example of ergotism is associated with rye infected with Claviceps purpurea, which was known as St. Anthony's fire in medieval Europe. One of the consequences of eating contaminated rye is gangrene. Some of the victims of ergotism are depicted in the paintings of Pieter Breuegel (1525 - 1569) Because of our knowledge of the fungus, its effects and how to control it and prevent contamination of food, ergotism rarely occurs.

An early print showing sclerotia of the fungus Claviceps purpurea which replace the seed in head of rye.

Ergot on dallis grass. This is caused by the fungus Claviceps paspalis. Ergotism is an occasional problem in Texas when livestock have fed on infected grass.

Disclaimer:  The information given is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Texas Agricultural Extension Service or Texas A&M University is implied. Extension programs serve people of all ages regardless of socioeconomic level, race, color, sex, religion, disability or national origin. The Texas A&M University System, U.S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating.