Albert Hofmann, the father of the mind-altering drug LSD whose medical discovery grew into a notorious “problem child,” has died at 102.

Hofmann died on Tuesday of a heart attack at his home in Basel, Switzerland, according to Rick Doblin, president of the Multidisciplinary Association for Psychedelic Studies, in a statement posted on the association’s website.

Hofmann’s hallucinogen inspired — and arguably corrupted — millions in the 1960’s hippy generation. For decades after LSD was banned in the late 1960s, Hofmann defended his invention.