In 1917, Julius Wagner von Jauregg (Austrian psychiatrist and neurologist) began inoculating paretics (psychosis associated with neurosyphilis) with blood from patients with benign tertian malaria caused by Plasmodium vivax (protozoan parasite that causes vivax malaria). The elevated temperature of the body caused by the malaria parasite killed the temperature sensitive "Treponema pallidum" (a microscopic bacterial organism that causes syphilis).

Institutions for malariotherapy rapidly spread throughout Europe and the technique was also adopted in several centers in the United States. In this way, thousands of syphilitics were saved from a sure and agonizing death.