Joseph Lister pioneered the use of antiseptics in surgery in the 1860s after learning about Louis Pasteur's germ theory. He discovered that using carbolic acid to clean wounds and instruments significantly reduced post-operative infections. Death rates from surgery fell dramatically. Later, the use of steam sterilization and aseptic techniques like masks and gloves further reduced surgical infections and improved outcomes. Ignaz Semmelweis similarly reduced maternal mortality in the 1840s by insisting doctors wash their hands with chlorinated water before deliveries. This helped establish germ theory and antiseptic practices in surgery.