Peyote is a small, spineless cactus, Lophophora williamsii, whose principal active ingredient is the hallucinogen mescaline. From earliest recorded time, peyote has been used by natives in northern Mexico and the southwestern United States as a part of traditional religious rites.
The top of the cactus above ground -- also referred to as the crown -- consists of disc-shaped buttons that are cut from the roots and dried. These buttons are generally chewed or soaked in water to produce an intoxicating liquid. The hallucinogenic dose for mescaline is about 0.3 to 0.5 grams (equivalent to about 5 grams of dried peyote) and lasts about 12 hours. While peyote produced rich visual hallucinations which were important to the native peyote cults, the full spectrum of effects served as a chemically induced model of mental illness. Mescaline can be extracted from peyote or produced synthetically.
A resurgence of interest in the use of peyote was spawned by accounts of its use in the early works of writer Carlos Castaņeda. Don Juan Matus, the pseudonym for Castaņeda's instructor in the use of peyote, used the name "Mescalito" to refer to an entity that purportedly can be sensed by those using peyote to gain insight in how to live one's life. Later works of Castaņeda indicated that the use of such psychotropic substances was not necessary to achieve heightened awareness and de-emphasized the use of peyote as a general means to achieve this end.