Chemical, the US Army, major pharmaceutical companies, and other sponsors conducted a wide variety of research on prisoners-a captive, vulnerable, and easily accessible population. 1,2 During that time, approximately 90% of all pharmaceutical research was conducted on prisoners, who also were subjected to biochemical research ranging from testing diet drinks and simple detergents to studies involving dioxin and chemical warfare agents. 3 From 1962 to 1966, for example, 33 pharmaceutical companies tested 153 experimental drugs at Holmesburg Prison in Philadelphia, including a Retin-A (tretinoin) study in which researchers did not seek informed consent and prisoners were not adequately treated for pain. 4 By the mid-1970s, biomedical research in prisons sharply declined as knowledge of the exploitation of prisoners began to emerge and the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research was formed. 5 Federal regulations to protect human subjects of research were established in 1974 and modified and codified in 1981. 6 The regulations were revised in 1991 as the Federal Policy for the Protection of Human Subjects and became known as the Common Rule. The Common Rule applies to research funded by the Department of Health and Human Services (DHHS); to private institutions that undertake a Federal-Wide Assurance of Compliance; and, with broad exceptions, to 16 additional federal agencies. 6 The US Food and Drug Administration has similar regulations for research involving the products it regulates. The Common Rule contains requirements for institutional review board (IRB) review, informed consent, and risk/benefit analysis.These regulations also provide extra protections for particularly vulnerable populations: pregnant women, fetuses, and neonates (subpart B); prisoners (subpart C); and children (subpart D). Subpart C, promulgated in 1978 in response to recommendations from the national commission, 7 strictly limits research involving prisoners. However, federal agencies (except for the DHHS, Central Intelligence Agency, and Social Security Administration) have not adopted subpart C, perhaps because it is so restrictive. In 1981, Food and Drug Administration regulations spe-