Some fungi produce toxins that cause severe illness when ingested. One bite of the mushroom Amanita muscaria is enough to kill a person within a few days. It produces a potent neurotoxin . Symptoms of gastritis are followed by liver damage. Some mushrooms in the genus Psilosybe produce mind-altering compounds that induce trances and hallucinations.
Aflatoxin is made by the fungus Aspergillus flavus.
Aspergillus flavus is commonly found growing on and decomposing grains and nuts. Aflatoxin is converted into a potent carcinogen by the action of liver enzymes. Ergot alkaloids are produced by the fungus Claviceps purpurea. This fungus grows on the seed heads of many grasses, especially rye. Today, grains that are rotting due to fungal growth are discarded.