Psychedelics are a hallucinogenic class of psychoactive drug whose primary effect is to trigger non-ordinary states of consciousness and psychedelic experiences via serotonin 2A receptor agonism. This causes specific psychological, visual and auditory changes, and often a substantially altered state of consciousness. “Classical” psychedelic drugs include mescaline, LSD, psilocybin, and DMT. psychedelics are a boon to psychiatry, a menace to society, or a gateway to another realm. The most well-known members of the group are LSD, DMT, mescaline and psilocybin. LSD was discovered in 1943, but the others are produced by plants and fungi, and have been used by various cultures to induce altered states of consciousness for hundreds or thousands of years.