When Was Penicillin Discovered?

In September 1928, Scottish bacteriologist Alexander Fleming returned from holiday to his laboratory at St Mary Hospital in London and noticed something unusual: a petri dish of Staphylococcus bacteria had been contaminated by a mould, later identified as Penicillium notatum, and the bacteria near the mould had been killed. Fleming published his findings in 1929 but did not pursue mass production. In the early 1940s, Howard Florey and Ernst Boris Chain developed methods to purify and mass-produce penicillin, which became widely available by 1945 and saved countless lives during World War II. All three shared the 1945 Nobel Prize in Physiology or Medicine.