The syphilis experiments in Guatemala were United States-led human experiments conducted in Guatemala from 1946 to 1948. It was done during the administration of American President Harry S. Truman and Guatemalan President Juan José Arévalo with the cooperation of some Guatemalan health ministries and officials. Doctors infected soldiers, prostitutes, prisoners and mental patients with syphilis and other sexually transmitted diseases, without the informed consent of the subjects, and treated most subjects with antibiotics. This resulted in at least 83 deaths. In October 2010, the U.S. formally apologized to Guatemala for conducting these experiments.
The experiments were led by physician John Charles Cutler who also participated in the late stages of the Tuskegee syphilis experiment.
The experiments were led by United States Public Health Service physician John Charles Cutler, who had earlier participated in the similar Terre Haute prison experiments, in which volunteer prisoners were infected with gonorrhea. In archived documents, Dr. Thomas Parran, Jr., the U.S. Surgeon General at the time of the experiments, acknowledged that the Guatemalan work could not be done domestically, and details were hidden from Guatemalan officials.
The experiments were funded by a grant from the U.S. National Institutes of Health (NIH) to the Pan American Sanitary Bureau and involved multiple Guatemalan government ministries. A total of about 1500 study subjects were involved although the findings were never published.