Ergot is a disease of rye caused by the fungus Claviceps purpurea. It is characterized by the presence of dark sclerotia on the infected grains, which can cause poisoning if consumed. Ergotism, the name for the condition caused by ERGOT, can lead to severe symptoms such as hallucinations, convulsions, and even death. ERGOT has been known since ancient times and was used in some cultures as a medicine.