What is LSD?

LSD or acid (lysergic acid diethylamide) is the most commonly used hallucinogen (also known as psychedelics). It is considered a typical hallucinogen causing similar effects to other hallucinogens like mescaline, psilocybin (mushrooms), and ibogaine. LSD became popular in the counterculture of the 1960s and 1970s, but since then its use has been limited to people in the Rave or club scenes.