The subsequent Nuremberg trials begin with the Doctors' Trial, prosecuting physicians and officers alleged to be involved in Nazi human experimentation and mass murder under the guise of euthanasia.

The subsequent Nuremberg trials were twelve military tribunals for war crimes committed by the leaders of Nazi Germany (1933–1945). The Nuremberg Military Tribunals occurred after the Nuremberg trials, held by the International Military Tribunal, which concluded in October 1946. The subsequent Nuremberg trials were held by U.S. military courts and dealt with the cases of crimes against humanity committed by the business community of Nazi Germany, specifically the crimes of using slave labor and plundering occupied countries, and the war-crime cases of Wehrmacht officers who committed atrocities against Allied prisoners of war, partisans, and guerrillas.

United States of America v. Karl Brandt, et al., commonly known as the Doctors' Trial, was the first of the twelve "Subsequent Nuremberg trials" for war crimes and crimes against humanity after the end of World War II between 1946 and 1947. The accused were 20 physicians and 3 SS officials charged for their involvement in the Aktion T4 programme and Nazi human experimentation.

Nazi human experimentation was a series of medical experiments on prisoners by Nazi Germany in its concentration camps mainly between 1942 and 1945. There were 15,754 documented victims, of various nationalities and ages, although the true number is believed to be more. About a quarter of documented victims were killed and survivors generally experienced severe permanent injuries.

Aktion T4 was a campaign of mass murder by involuntary euthanasia which targeted people with disabilities and the mentally ill in Nazi Germany. The term was first used in post-war trials against doctors who had been involved in the killings. The name T4 is an abbreviation of Tiergartenstraße 4, a street address of the Chancellery department set up in early 1940, in the Berlin borough of Tiergarten, which recruited and paid personnel associated with Aktion T4. Certain German physicians were authorised to select patients "deemed incurably sick, after most critical medical examination" and then administer to them a "mercy death". In October 1939, Adolf Hitler signed a "euthanasia note", backdated to 1 September 1939, which authorised his physician Karl Brandt and Reichsleiter Philipp Bouhler to begin the killing.