Penicillin

Penicillin is a group of antibiotics that changed the treatment of bacterial infections. Its story began in 1928, when Scottish bacteriologist Alexander Fleming noticed that a mold had accidentally grown on one of his laboratory culture plates. Around the mold, bacteria were not growing. Fleming identified the mold as belonging to the genus Penicillium and named the antibacterial substance it produced “penicillin”.

He published his findings in 1929, but the discovery did not immediately become a widely used medicine. Producing enough purified penicillin for treatment proved difficult, and further research was needed to understand its properties. Fleming's observation nevertheless opened the way to a new class of medicines that could act against certain bacteria without directly attacking human cells.

During the late 1930s and early 1940s, researchers Howard Florey, Ernst Chain and their colleagues at Oxford worked on extracting, purifying and testing penicillin. Their efforts helped turn Fleming's laboratory observation into a practical treatment. In 1941, penicillin was successfully used to treat patients with serious bacterial infections, and methods for producing it on a much larger scale were developed during the Second World War.

Large-scale production made the drug increasingly available and helped reduce deaths from several bacterial diseases. Fleming, Florey and Chain received the Nobel Prize in Physiology or Medicine in 1945 for their work on penicillin. The discovery also revealed an important limitation: bacteria can develop resistance to antibiotics. Penicillin therefore became both a landmark in medicine and a reminder that antibiotics must be used carefully and responsibly.