LSD, chemically known as d-lysergic acid diethylamide, is a most powerful known hallucinogen - A psychoactive drug that induces hallucinations or altered sensory experiences by radically changing a person's mental state by distorting the perception of reality. It is better known by the name of "acid" on the street. It was discovered in 1938 from a fungus that grows on rye and other grains. However due to its widespread illicit use, LSD is chemically manufactured nowadays.