Ergotism is a condition caused by consuming grains contaminated with the fungus Claviceps purpurea, which contains alkaloids that act as vasoconstrictors. Historically, ergotism epidemics in Europe were caused by consumption of ergot-infected rye bread. Symptoms include convulsions, gangrene of extremities due to restricted blood flow, hallucinations and psychosis. However, some ergot alkaloids such as ergotamine are used medicinally to treat migraines and postpartum hemorrhage when administered properly.