Lysergic acid diethylamide, also known as acid, is a hallucinogenic drug.

LSD was first made by Albert Hofmann in 1938 from lysergic acid, a chemical from the fungus ergot. LSD is considered an entheogen because it can catalyze intense spiritual experiences, during which users may feel they have come into contact with a greater spiritual or cosmic order. Users sometimes report out of body experiences. In 1966, Timothy Leary established the League for Spiritual Discovery with LSD as its sacrament.