The discovery of penicillin in 1928 by Alexander Fleming marked a turning point in modern medicine. This antibiotic, derived from the mold Penicillium notatum, revolutionized the treatment of bacterial infections. Prior to its discovery, there were limited options for treating such infections, which could often lead to severe health complications or death. The introduction of penicillin saved countless lives and paved the way for the development of other antibiotics, advancing the field of medicine significantly.