This study was conducted in the United States and was designed to determine the natural history of untreated latent syphilis. Over 400 black men with syphilis and about 200 men without syphilis, who served as the controls, were the subjects.
The men were recruited without informed consent. In fact, they were misinformed and told that some of the procedures done in the interests of research (e.g., spinal taps) were actually “special free treatment.”

By 1936, it was apparent that many more infected men than controls had developed complications.  Ten years later a report of the study indicated that the death rate among those with syphilis was about twice as high as it was among the controls.

In the 1940’s, when penicillin, known to be effective in the treatment of syphilis, became available, the men were neither informed of this, nor treated with the antibiotic.

The study continued until the first accounts of it appeared in the national press in 1972, at which time an ad hoc advisory panel was formed by the government to give advice on how to assure that such experiments would never again be conducted.

The government continues to pay millions of dollars yearly to surviving subjects and the families of deceased subjects.