Alexander Fleming

Alexander Fleming was a Scottish physician and microbiologist who discovered penicillin, the world's first true antibiotic. His accidental observation of mold inhibiting bacterial growth in a petri dish led to a medical revolution, saving millions of lives from previously fatal infections. Fleming's work laid the foundation for the development of modern antibiotic therapy. He also discovered the enzyme lysozyme, contributing to our understanding of the body's innate immune system.

His legacy is one of the most significant medical breakthroughs in history, fundamentally changing the treatment of infectious diseases.