Some hallucinogens come from natural sources such as mescaline from the peyote cactus.
Others, such as LSD, are synthetic or manufactured. However, it does not fit easily into any one drug category because it also can relieve pain or act as a stimulant. It is considered a hallucinogen but is somewhat different because it also can relieve pain or act as a stimulant. It was first developed as an animal anesthetic in the 1950's. However, it was taken off the market for human use because of its hallucinogenic effects.