Emil von Behring developed diphtheria antitoxin and won the first Nobel Prize in Physiology or Medicine in 1901.
Behring’s work showed that blood serum could contain substances capable of neutralizing bacterial toxins. Working with Shibasaburo Kitasato, he demonstrated antitoxin activity against diphtheria and tetanus, helping establish serum therapy as a practical medical treatment.
Diphtheria was a major childhood killer in the late nineteenth century. Antitoxin did not work like a modern preventive vaccine: it supplied ready-made antibodies for treatment or temporary protection. Later vaccination programs stimulated the patient’s own immune system instead.
Behring shared credit for the underlying discoveries with other researchers, but the 1901 Nobel award specifically recognized his work on serum therapy, especially against diphtheria. Paul Ehrlich later made important contributions to antibody theory and immunology.