- Bicycle Day on April 19 honors not the two-wheeled mode of transportation, but the colorful ride taken by Swiss chemist Albert Hoffman who accidentally discovered LSD on 19 April 1943.
- Bicycle Day celebrates Swiss scientist Albert Hofmann's discovery of lysergic acid diethylamide or LSD in 1943, and the subsequent, and at times harrowing, ride home on his bicycle after deliberately ingesting a dose of the drug.
- In search of new medicines, Hoffman was trying to stabilize lysergic acid, a derivative of a fungal compound used in a migraine medicine.
- He ended up synthesizing a compound called lysergic acid diethylamine, or LSD. Later, he accidentally exposed himself to it and felt dizzy with hallucinations. On Bicycle Day, he took 250 µg of LSD intentionally and, fearing he had made himself ill, cycled home from his lab.
- On April 19, 1943, he tested it on himself again and needed a lab assistant to help him home, via bicycle, leading to a memorable ride.
- While recreational drug abuse led to bans on psychedelics in the 1970s, new research indicates Hoffman was onto something in his search for medicines that led to LSD. The approach may now yield potential mental health treatments.
- He wrote about his experiments and experience on April 22, which was later put into his book LSD: My Problem Child.
- Stephen Bright from Curtin University's School of Psychology conceded it might seem a little odd to celebrate the discovery of an illegal drug, but said there was much more to LSD than many people realised. Dr Bright said the discovery of LSD's psychedelic properties led to a new understanding of the brain, and a paradigm shift in psychiatry.
- The events of the first LSD trip, now known as “Bicycle Day”, after the bicycle ride home, proved to Hofmann that he had indeed made a significant discovery: a psychoactive substance with extraordinary potency, capable of causing significant shifts of consciousness in incredibly low doses.
- Hofmann foresaw the drug as a powerful psychiatric tool; because of its intense and introspective nature, he couldn’t imagine anyone using it recreationally. Bicycle Day is increasingly observed in psychedelic communities as a day to celebrate the discovery of LSD.
- The celebration of Bicycle Day originated in DeKalb, Illinois, in 1985, when Thomas B. Roberts, then a Professor at Northern Illinois University, invented the name "Bicycle Day" when he founded the first Bicycle Day celebration at his home. Several years later, he sent an announcement made by one of his students to friends and Internet lists, thus propagating the idea and the celebration.
- His original intent was to commemorate Hofmann's original, accidental exposure on April 16, but that date fell midweek and was not a good time for the party, so he chose the 19th to honor Hofmann's first intentional exposure.