Medical experiments on animals and humans have led to major treatment advances and saved and improved the lives of millions of people. Not all of these experiments were ethical, however. In the 21st century, some of the most racist (and famous) experiments took place that could never happen today.

In the video, "10 Racist Medical Experiments," AllTime10s explains that medical studies should be conducted for the benefit of humanity, but people who were in vulnerable positions, such as racial minorities and prisoners, were forced into the role of the human guinea pig. Today, experiments must abide by the American Psychological Association’s (APA) Code of Conduct, which pertains to everything from confidentiality, to consent, to overall beneficence. APA's Code of Conduct required psychological experiments to be ethical. Review boards enforce these ethics to prevent experiments like the following from occurring.

Starting in the early 1930s to mid 1970s, the U.S. government denied 400 African American men treatment for the deadly disease syphilis as part of a racist medical experiment known as the Tuskegee syphilis experiment. This is known as one of the most prolonged and knowingly unethical medical experiments in America's recent history. Researchers observed poor and uneducated African American men who had been diagnosed with syphilis in order to see whether the disease affected them differently than white men. These men weren't told the nature of their disease, and given placebos as treatment, even though by 1947 penicillin became the standard cure for the disease. The experiment came to an end after being exposed by journalists, but only 74 participants were still alive.

Meanwhile in America's colony, Puerto Rico, the efficacy of birth control, specifically the pill, was studied on Puerto Rican women of color. In 1955, oral contraceptives couldn't be brought to the market until researchers conducted large-scale human trials to prove the pill was safe. These vulnerable women weren't told that the pill was only in its experimental stages, nor were they warned of any potential dangerous side effects.

A year later, the pill was deemed effective at preventing pregnancy, but 17 percent of women suffered debilitating side effects, including vomiting, headaches, and stomach pain. Three died during the experiment, but there was no follow-up investigation.

America's most vulnerable were also the subjects of carcinogen injections, like Agent Orange. Dr. Albert Kligman, lead researcher of this experiment, used African American prisoners at Holmesburg Prison as subjects in what was deemed “dermatological research.” The dermatology component was testing out the effects of Agent Orange on the skin by injecting dioxin (a main component of Agent Orange). It’s rumored Kligman injected 468 times the amount he was authorized to use. In a 1966 newspaper interview, Kligman recalled:

“All I saw before me were acres of skin… It was like a farmer seeing a fertile field for the first time.”

View the rest of Alltime10s video to see the most disturbing racist experiments in the 20th century.