Today in History is a daily newsletter from Britannica. (more) Today in History—April 19: The Very First Acid Trip in History Written by Michele Metych Michele Metych is the lead editor for Today in History at Encyclopædia Britannica. Michele Metych Fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors Last updated Apr. 16, 2026 •History On this day in 1943, Swiss research chemist Albert Hofmann conducted an outlandish experiment—on himself. He dosed himself with 0.25 milligrams of lysergic acid diethylamide, and then he…went for a bike ride. Today in History is a daily newsletter from Britannica. Encyclopædia Britannica, Inc. Want to learn more about what happened on April 19, or any other day of the year? Sign up to receive the newsletter in your inbox every morning. Hofmann’s work focused...

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