The Tuskegee Study of Untreated Syphilis in the Negro Male(informally referred to as the "Tuskegee Syphilis Experiment,")  was an ethically abusive study conducted between 1932 and 1972 by the United States Public Health Service (PHS) and the Centers for Disease Control and Prevention  The purpose of this study was to observe the natural history of untreated syphilis. Although the African-American men who participated in the study were told that they were receiving free health care from the federal government of the United States, they were not,