Ergot is a type of fungus that primarily infects cereal grains, especially rye. It produces dark, elongated structures called sclerotia, which can be toxic to humans and animals if ingested. Historically, ergotism, a condition caused by consuming contaminated grains, led to severe health issues, including hallucinations and gangrene. The active compounds in ergot, such as ergotamine, have been studied for their medicinal properties. They are used in treating migraines and other conditions, but their toxicity requires careful management. Today, ergot is mostly controlled in agriculture to prevent contamination of food supplies.