17. Ignaz Semmelweis (also known for introducing hand disinfection standards in hospitals)

Ignaz Semmelweis was a Hungarian physician in the 19th century who discovered that handwashing could significantly reduce infections in hospitals, particularly during childbirth. He observed that doctors who didn’t wash their hands could transfer deadly germs from cadavers to patients, leading to high death rates from puerperal fever. Semmelweis advocated for rigorous hand disinfection, which drastically lowered mortality rates in the maternity ward. Despite facing resistance from the medical community, his work laid the foundation for modern hygiene practices in healthcare, emphasizing the importance of cleanliness in preventing disease transmission. His contributions are recognized as a pivotal advancement in medical safety.