Psychedelic drug derived from a small, spineless cactus Lophophora williamsii of N Mexico and the SW US, known as peyote. The tops (called mescal buttons), which scarcely appear above ground, are dried and chewed, or added to alcoholic drinks. Mescaline is a crystalline alkaloid C11H17NO3. It is used by some Native Americans in religious rites.
The hallucinatory alkaloid that is the active agent in mescal buttons; SYN. peyote.