Which treatment earned Emil von Behring the first Nobel Prize in Physiology or Medicine?

Diphtheria antitoxin earned Emil von Behring the first Nobel Prize in Physiology or Medicine.

Behring received the inaugural medicine Nobel Prize in 1901 for his work on serum therapy, particularly its application against diphtheria. Working with Japanese bacteriologist Shibasaburo Kitasato, he showed that blood serum from animals immunized against diphtheria could neutralize the disease’s toxin. The protective substance became known as antitoxin.

Diphtheria was a major childhood killer in the late nineteenth century. Antitoxin treatment did not prevent infection in the way a vaccine does, but it could neutralize toxin after illness began and dramatically improve survival. Serum was produced by immunizing animals, especially horses, and collecting antibody-rich blood products.

Behring’s recognition helped establish immunology and serum therapy as major medical disciplines. Diphtheria toxoid vaccines later provided active protection and became part of routine childhood immunization. Antitoxin and vaccine are therefore related but distinct: one treats toxin exposure, while the other trains the immune system in advance.