Susan M Reverby has unearthed a glaring example of unethical research, carried out by the United States Public Health Service and co-sponsored by the National Institutes of Health, the Pan American Health Sanitary Bureau and the Guatemalan government in 1946-48. In this study of the effectiveness of penicillin in syphilis and gonorrhoea, 700 Guatemalan nationals including prison inmates, mentally challenged people and military personnel were intentionally infected with various sexually transmitted diseases including syphilis and gonococcal infection. Prison inmates were allowed to have sex with syphilis-infected prostitutes paid by US health officials. There are no records on whether informed consent was obtained from the subjects participating in the trial.