Giuseppe Sanarelli (24 September 1865 – 6 April 1940) was an Italian bacteriologist who incorrectly identified the cause of yellow fever as a bacterium. It was however found later by Walter Reed that the bacterium Bacillus icterioides was a secondary infection. In 1897 he triggered the first major public debate on medical ethics when he injected yellow fever bacteria into five patients without consent, three of whom died. He also served as a senator of the Kingdom of Italy from 1920 to 1940.