LSD or Lysergic Acid Diethylamide.
A drug discovered by the Swiss psychiatrist Albert Hoffman in 1943. The hallucinogenic effects of this drug became very popular in the 1960s. Frank Zappa expressed the belief that the American government used LSD in the 1960s as an experiment to prevent possible youth rebellions:
"They were just so full of dope that they were going blindly their own way, not thinking for a moment that the origin of LSD was in the CIA and a lot of them probably don't like to think about that now. By taking LSD they were helping the CIA in one of their favorite experiments. After they got done taking volunteers from the army, they actually made a profit selling it to people on the street, and seeing what actually happened to a civilian population. They got it in the ass so bad from the CIA that they don't even know. So to sit on the outside of that and say it was stupid will not make you any friends in the group of people who really believe in it, and since there were more of them than of me, it sort of set me up in a negative light for all the years to come. (...) They're a cultural phenomenon, they're an industry, and they're a tool by which the government keeps the kids in check. They also use the same thing to keep the housewives down. Every time you take some dope and you think you're getting some escape from your life, you're just playing right into the government's hand. Everytime you use whatever it is that you use, you're registering yourself as a pawn. (...) The minute you start taking those drugs, they got you. I'd rather be free inside of my mind. If you don't have enough money to beat the system, the least you can do is keep your self-respect and know what you think is not chemically induced by a governmental agency."