The Belmont Report 

The National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research issued "The Belmont Report: Ethical Principles and Guidelines for the Protection of Human Subjects of Research." The report sets forth three principles underlying the ethical conduct of research: Respect for persons, Beneficence, and Justice. The Belmont Report explains how these principles apply to research practices. In response to the report, both the U.S. Department of Health and Human Services and the U.S. Food and Drug Administration revised their regulations on research studies that involve people.

The Nuremburg Code

 Developed in response to the Nuremberg Trials of Nazi doctors who performed unethical experimentation during World War II, the Code was the first major international document to provide guidelines on research ethics. It made voluntary consent a requirement in clinical research studies, emphasizing that consent can be voluntary only if participants are able to consent; they are free from coercion (i.e., outside pressure); and they comprehend the risks and benefits involved. The Code also states that researchers should minimize risk and harm, make sure that risks do not significantly outweigh potential benefits, use appropriate study designs, and guarantee participants' freedom to withdraw at any time.

The Declaration of Helsinki

At the 18th World Medical Assembly in Helsinki, Finland, the World Medical Association adopted 12 principles to guide physicians on ethical considerations related to biomedical research. It emphasizes the distinction between medical care that directly benefits the patient and research that may or may not provide direct benefit. These guidelines were revised at subsequent meetings in 1975 (Tokyo, Japan), 1983 (Venice, Italy), 1989 (Hong Kong), 1996 (Somerset West, Republic of South Africa) and 2000 (Edinburgh, Scotland).