In 1928, Alexander Fleming returned from vacation and accidentally discovered penicillin, the medical breakthrough that became the world's most widely used antibiotic

Sir Alexander Fleming discovered penicillin accidentally in 1928 after returning from vacation. Howard Florey and Ernst Chain later developed methods to purify this substance. Penicillin became a crucial medicine during World War II, saving many soldiers. This antibiotic revolutionized medical care by treating previously deadly infections. Penicillin laid the groundwork for numerous other life-saving antibacterial drugs.