The discovery of penicillin in 1928 by Alexander Fleming had a profound impact on global health. It marked the beginning of the antibiotic era, revolutionizing the treatment of bacterial infections and significantly reducing mortality rates. Penicillin's effectiveness against previously life-threatening diseases transformed medical practice, allowing for safer surgeries and improved healthcare outcomes. This breakthrough sparked the development of additional antibiotics, changing the course of medicine and public health. It remains one of the most significant advancements, influencing the treatment of infectious diseases worldwide.