Alexander Fleming
Discovered Penicillin — Saved 200 Million Lives
The Accidental Leo Who Saved Millions
Alexander Fleming discovered penicillin in 1928 by noticing that mold had contaminated one of his petri dishes and killed the bacteria around it. A less curious scientist would have discarded the dish. A Leo’s curiosity kept it. That moment of noticing is considered the most consequential accidental discovery in medical history — penicillin has saved an estimated 200 million lives.
Leo Legacy
- Penicillin discovery: 1928 — observed mold killing bacteria, the key moment in medical history
- Nobel Prize: Medicine, 1945 — shared with Howard Florey and Ernst Chain
- 200 million lives saved: Penicillin’s estimated impact on human survival
- Professor of bacteriology: St. Mary’s Hospital London — where the discovery occurred
Fleming’s Leo gift was seeing what others overlooked — and recognizing its extraordinary importance.
“One sometimes finds what one is not looking for.”