Albert Hofmann, the Swiss inventor who discovered the hallucinogenic drug lysergic acid diethylamide-25 (LSD), died of a heart attack at his home in Basel at the age of 102.

For decades after LSD was banned in the late 1960s, Hofmann defended his invention. “I produced the substance as a medicine. ... It's not my fault if people abused it,” he once said, according to the Associated Press.

The chemist first produced LSD in 1938 while researching the medicinal uses of a fungus found on wheat and other grains at the Sandoz pharmaceuticals firm in Basel. It appears he accidentally ingested some of the drug and declared later “Everything I saw was distorted as in a warped mirror,” BBC News reports.

“What I was thinking appeared in colors and in pictures… It lasted for a couple of hours and then it disappeared,” the chemist old Swiss television network SF DRS for a program marking his 100th birthday two years ago.

Hoffmann and his scientific colleagues thought LSD could be used in order to treat mental illness like schizophrenia. However, LSD was popularized by Harvard professor Timothy Leary who suggested that people “turn on, tune in, drop out,” and became a popular street drug in the 1960s.

Albert Hofmann agreed that LSD was dangerous if in the wrong hands. This was reflected by the title of his 1979 book: “LSD - my problem child.” The chemist retired from Sandoz in 1971 and he devoted his time to travel, writing and lectures.