TIME

Discovery of Penicillin

1928

A small brass case with a glass window holding a sample of penicillium mould, labeled from Professor Alexander Fleming, 1935.

Recorded HistoryDiscovery of Penicillin

In 1928 Alexander Fleming, a bacteriologist at St Mary’s Hospital in London, returned from a holiday in early September to find a plate of Staphylococcus bacteria contaminated by a mould, Penicillium notatum, with a clear ring around it where the bacteria had not grown. He published his findings in 1929.

Fleming did not develop it into a drug. Howard Florey, Ernst Chain, and Norman Heatley at Oxford purified penicillin from 1939 and tested it on patients in 1941, and mass production in the United States during the Second World War made it widely available. Fleming, Florey, and Chain shared the 1945 Nobel Prize in Physiology or Medicine. The sample pictured dates from 1935, not 1928.

1928, placed on the scale of its era on a line leading toward now.

Era
Recorded History
Period
1928
Edition
1/1
Status
Reserved for a Future Release
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Background artwork

Cinematic background showing a laboratory bench with a microscope and culture dishes. An illustration generated with an AI image tool for TIME. It is an artistic depiction, not a photograph or a record of the moment. The scene is imagined and not a photograph of Fleming's laboratory.