Tolerance to mescaline develops rapidly with continued abuse, but it is not considered physiologically addictive and withdrawal symptoms do not occur.
Mescaline, is the active principle of the cactus peyote Loporophora williamsii which grows wild in certain parts of Mexico and the southern and western USA. It is a favourite ritualistic hallucinogen, one of several still used in religious and healing ceremonies practised by some American Indians.