Ethnomycology is the study of the historical uses and sociological impact of fungi and can be considered a subfield of ethnobotany or ethnobiology. Although in theory the term includes fungi used for such purposes as tinder, medicine (medicinal mushrooms) and food (including yeast), it is often used in the context of the study of psychoactive mushrooms such as psilocybin mushrooms, the Amanita muscaria mushroom, and the ergot fungus.