Tuskegee Syphilis Study nurse Eunice Rivers visiting a patient in the cotton fields of Macon County, circa 1932. The Tuskegee Syphilis Study was carried out in Macon County, Alabama, USA, from 1932 to 1972 by the United States Public Health Service. Its objective was to study the natural course of untreated syphilis. The study recruited 600 poor African Americans, 399 of whom had syphilis. Participants were not told their diagnosis and were only treated with placebos, even after penicillin was found to be an effective treatment for the disease. Of the original participants, 28 died as a result of syphilis and a further 100 of complications of the disease, 40 wives were infected and 19 children born with congenital syphilis. Condemnation of the study lead to congressional acts and laws that regulated human clinical trials, ensured informed consent and protected participants.