 Syphilis experiments were also carried out in Guatemala from 1946 to 1948 . They were United States @-@ sponsored human experiments , conducted during the government of Juan José Arévalo with the cooperation of some Guatemalan health ministries and officials . Doctors infected soldiers , prisoners , and mental patients with syphilis and other sexually transmitted diseases , without the informed consent of the subjects , and then treated them with antibiotics . In October 2010 , the U.S. formally apologized to Guatemala for conducting these experiments . 
