psychotomimetics, substances of plant origin and synthetic compounds capable of causing in healthy persons functional disturbances of the central nervous system similar to psychoses, especially hallucinations. Hallucinogens include alkaloids isolated from the Mexican cactus (mescaline), from some species of Mexican mushrooms (psilocybin, etc.), and from harmal roots (harmine); semisynthetic derivative of the alkaloid ergot, diethylamide lysergic acid (LSD-25); Indian hemp (hashish); and some synthetic cholinolytic agents. Hallucinogens cause mental disturbances manifested by auditory and visual hallucinations, a sense of fear, and impairment of correct perception of the environment. Disturbances of the autonomic functions are also observed. Hallucinogens are sometimes used for diagnostic purposes to detect mental illnesses with a torpid or latent course and to create “models” of psychosis in experiments with animals. Repeated consumption of hallucinogens may result in habituation and severe nervous disorders.