Even though penicillin production was a complex collective work, Sir Alexander Fleming, the discoverer of the substance, was credited the most for this miracle antibiotic. He became the most recognized figure worldwide in relation to the penicillin success, and he was named a ‘benefactor of the mankind’. Penicillin mass production and application during and after the WWII gained enormous public attention through the Media, and Fleming was invited to give lectures and collect awards from all over the globe. We put forward a new look on this hype of the time, through the previously unpublished material of Fleming’s archive that is located in Athens, Greece. This archive was preserved by Amalia Fleming, the second wife of Alexander Fleming, who after his death in 1955, returned to Greece from England and took with her most of Fleming’s notebooks, photographs from the trips and the ceremonies, awards and gifts, newspaper’s clips concerning Fleming and penicillin, and a bulk of letters addressed to him. This archive is now being registered and organized, and this is the first attempt to communicate this historical treasure. We examine how Fleming’s travels and publicity diffused knowledge on the penicillin miracle and raised the expectations on medical progress. Even though Fleming was very cautious on the use of penicillin as a panacea, the media and people’s hopes eventually overwhelmed the public imagination on the abilities of penicillin. We see how the expert tried to control these reactions through numerous letters, interviews and responds to requests. We also look at how the ‘accidental’ nature of Fleming’s discovery played its role in the construction of Fleming’s legend. Our approach is putting forward questions of media coverage of science and technology, the construction of scientific facts, the image making of the scientist, but also we examine the hidden debates inside scientific community, concerning the credit of scientific discoveries. Penicillin’s success kicked off the antibiotic saga of 20th century, putting medicine in a new era. Public knowledge about this new drug was therefore a key instrument on the later promotion and development of other medical breakthroughs.