On Nov. 16, 1938, Albert Hofmann at Sandoz synthesized lysergic acid diethylamide (LSD). LSD-25, as originally known when first synthesized, was one in a long series of ergot-derived compounds were considered promising.

LSD-25, as it was known when Hofmann first synthesized, was originally just one in a long series of ergot-derived compounds that he considered promising. He hoped it would turn out to be an effective “circulatory and respiratory stimulant.” In animal tests, a modest clinical effect was noted, but mostly the subjects just became “restless.”

But Hofmann had had a “peculiar presentiment”, and five years later, on April 16, 1943, he made more, hardly knowing what he would do with it. The new batch amounted to a speck of a few centigrams. As he was finishing up, he was, in the words of the lab report he later scribbled, “interrupted” by a feeling of dizziness that obliged him to abandon his desk and go home, where he lay down and was regaled with “an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colors.” Before long the genie escaped the bottle.