How did Joseph Lister’s use of antiseptics reduce infections after surgery?

Joseph Lister, often called the father of modern surgery, revolutionized medical practice by applying the germ theory to prevent postoperative infections.12

Influenced by the work of Louis Pasteur, who demonstrated that microorganisms cause fermentation and disease, Lister concluded that surgical sepsis—a common and often fatal infection—was caused by germs entering wounds. To combat this, he introduced an antiseptic technique using carbolic acid to create a chemical barrier between the wound and the surrounding environment.231

Lister’s method involved:
* Sterilizing surgical instruments and cleaning wounds with carbolic acid.1
* Disinfecting the air and the operating room to prevent contamination.1
* Protecting the surgical site from the surgeon’s hands and instruments.2

These measures were highly effective; in his own wards, surgical mortality rates dropped from 45 percent to 15 percent between 1865 and 1869. His fundamental principle—that bacteria must never gain entry into an operation wound—remains the cornerstone of modern surgical practice.21