Eighty years ago, on 19 April, 1943, Swiss chemist Albert Hofmann took the first intentional psychedelic trip with LSD. This discovery-trip had radical effects on culture and art (literature, visual arts, music, dance, cinema), becoming a symbol – both deified and demonised – of counterculture and the hippie movement. An author of works on this subject, Marcelo Leite is an award-winning journalist and columnist for the Brazilian newspaper Folha de S.Paulo, where he regularly writes about science and the environment. In this essay, he discusses the research that has been going on since the 1990s with a view to the pharmacological and therapeutic use of psychedelics, especially in neurology and psychiatry.