Hallucinogens Hallucinogens Hallucinogens, or psychedelics, are drugs that affect a person's perceptions, sensations, thinking, self-awareness, and emotions.
Some hallucinogens come from natural sources, such as mescaline from the peyote cactus.
Others, such as LSD, are synthetic or manufactured. LSD is manufactured from lysergic acid which is found in ergot, a fungus that grows on rye and other grains. LSD was discovered in 1938 and is one of the most potent mood-changing chemicals. It is odorless, colorless, and tasteless. LSD is sold on the street in tablets, capsules, or occasionally in liquid form.