The Discovery of The First Naturally Derived Antibiotic

In 1939, coinciding with the start of World War II, Dubos had reported the discovery of the first naturally derived antibiotic, tyrothricin, a compound of 20% gramicidin and 80% tyrocidine, from B. brevis. It was one of the first commercially manufactured antibiotics and was very effective in treating wounds and ulcers during World War II.