APA Dictionary of Psychology

n. a powerful hallucinogenic beverage made from the stems of a tropical South American woody vine, Banisteriopsis caapi, often with leaves from the plant Psychotria viridis. Ayahuasca has been used for centuries by indigenous peoples of the Amazon for religious, spiritual, and medicinal purposes and more recently in the United States and Europe for similar reasons. The pharmacologically active ingredients are harmine and harmaline from B. caapi and dimethyltryptamine (see DMT) from P. viridis. In smaller doses, these ingredients have psychedelic and euphoric effects but in larger doses cause nausea, vomiting, and tinnitus. Also called caapi; yagé.