The first successful antibiotic is penicillin, discovered by Alexander Fleming in 1928. This groundbreaking medical advancement was not fully utilized until the early 1940s during World War II. Penicillin proved to be effective against a wide range of bacterial infections, saving countless lives and shaping the field of medicine. Its discovery opened the door for the development of other antibiotics, drastically reducing mortality rates from bacterial diseases and transforming healthcare. Fleming's work marked the beginning of the antibiotic era, leading to significant advancements in surgical procedures and the treatment of infectious diseases.