Léon Charles Albert Calmette ForMemRS (12 July 1863 – 29 October 1933) was a French physician, bacteriologist and immunologist, and an important officer of the Pasteur Institute.
He discovered the Bacillus Calmette-Guérin, an attenuated form of Mycobacterium bovis used in the BCG vaccine against tuberculosis.
He also developed the first antivenom for snake venom, the Calmette's serum.