This paper describes Giulio Alfredo Maccacaro’s involvement (from the end of World War II to the 1970’s) in the renewal of medical epistemology, and of institutional and medical practice in Italy. Maccacaro develops a critical approach to the contemporary dominant medical paradigm - rooted in internal medicine - and puts forward an alternative social and epidemiological model, based on a scientific systemic approach, open to "contamination" with other disciplines such as "the new biology", statistics, sociology and politics. His interest in psychiatry - and specifically in Franco Basaglia’s work - is in line with his prime objective: the renewal of medicine. Maccacaro promotes a scientific shift from medicine as "science of disease" to medicine as "science of life and of the human being".
Keywords: Maccacaro, epidemiology, epistemological and institutional renewal of medicine, medicine and psychiatry, medicine and participation