Following Albert Hofmann’s discovery of LSD’s psychoactive properties in 1943, and previous to their scheduling as controlled substances, the psychedelic drugs were widely studied—six international conferences and hundreds of papers discussed their potential therapeutic usefulness. The observation that the frightening experience of delirium tremens sometimes led alcoholics to moderate their alcohol intake suggested to early psychedelic researchers that the “psychotomimetic” experience thought to be produced by LSD could be used to treat alcoholism. A number of hypothesis-generating studies employing a variety of research designs to examine this premise were completed, but relatively few controlled trials attempted hypothesis testing. After twenty-five years of study, a combination of flawed methodology, uneven results and social reprehension led to the abandonment of research on the therapeutic use of psychedelic drugs, leaving many avenues of inquiry unexplored and many questions unanswered. Today, after a thirty-year hiatus, this research is gradually being resumed, and there is renewed interest in the findings of previous studies. This article explores the history of one branch of psychedelic research, the therapeutic use of LSD in the treatment of alcoholism, and of the events that led to the relabeling of the “hallucinogens” as drugs of abuse.