Penicillin (Alexander Fleming)

Penicillin is the first widely-used antibiotic discovered by Alexander Fleming in 1928. He noticed that a mold called Penicillium notatum produced a substance that killed bacteria, preventing infections. This discovery revolutionized medicine, allowing doctors to treat bacterial infections effectively, reducing death rates from illnesses like pneumonia and scarlet fever. Penicillin works by targeting bacterial cell walls, causing the bacteria to burst and die, while leaving human cells unharmed. Its development marked the beginning of modern antibiotics, saving countless lives and paving the way for further research into infection control.