American Doctors at the Nuremberg Medical Trial

Evelyne Shuster. American Journal of Public Health. Volume 108, Issue 1. January 2018.

Three Hippocratic physicians played critical roles in the prosecution of 23 Nazi doctors charged with murder and torture for conducting lethal medical experiments on concentration camp prisoners. Two of the physicians, Leopold Alexander and Andrew C. Ivy, were Americans, and the other, Werner Leibbrandt, was German. At the 70th anniversary of the Doctors’ Trial it is fitting to recall the three’s influences and contributions to the formulation of strict research ethics rules, known as the Nuremberg Code. Their contributions help us better understand why they insisted on strict research rules and yet ultimately were unable to apply these rules to their own research. Exploring their contributions at Nuremberg may help us appreciate the continuing difficulty physician-researchers have with accepting public regulation of research.

The Doctors’ Trial, also known as the Nuremberg Medical Trial (1946-1947), is best known for its Nuremberg Code. Judged by almost any standard, this trial was remarkable. The 23 defendants were respected and distinguished medical scientists and physicians who were charged with murder and torture in the context of unspeakable medical experiments on concentration camp prisoners. That murder and torture are crimes that must be prosecuted and punished was indisputable, but, as chief prosecutor General Telford Taylor declared in his opening statement, “This is no mere murder trial.” He insisted that the court, “as an agent of the United States and as the voice of humanity, stamp these acts, and the ideas which engendered them, as barbarous and criminal.”

Three physicians, who proudly identified themselves as Hippocratic physicians sworn to “do no harm,” played commanding roles for the prosecution: 2 Americans, Leopold Alexander and Andrew C. Ivy, and 1 German, Werner Leibbrandt. Their influence on the judges and the Nuremberg Code were significant and deserve to be better known. John W. Thompson, a Canadian experimental psychiatrist and air force officer working for the British delegation, played a minor role. Like Alexander, Thompson gathered intelligence documents for the upcoming trial, interviewed defendants and victims of Nazi experiments, and held extensive discussions with Alexander and Ivy on medical crimes both before and during the trial. But because the trial was exclusively run by the US government, Thompson played no formal or official role in it.

At the 70th anniversary of the Doctors’ Trial, it is fitting to recall and explore how these physicians came to propose that the judges adopt strict research rules for the conduct of human experimentation and yet were unable to see their applicability to their own research. For them, Hippocratic physicians could do no wrong.

Leopold Alexander

Leopold Alexander, or “Leo” as he liked to be called, a Viennese-born American neuropsychiatrist, was no stranger to American and German medicine, including the experimental medical practices of the Third Reich. Born in Vienna in 1905 into an educated Jewish family, Alexander earned his medical degree from the University of Vienna and did his internship and residency in Germany at Frankfurt University. As the political situation in Germany deteriorated, he settled in the United States and became a US citizen in 1938. Shortly after, he joined the US Army Medical Corps and was stationed in England at the American Eighth Air Force base, where he specialized in the treatment of combat fatigue in bomber air crews. As the war ended, Alexander was detached on a special mission under the Combined Intelligence Operative Sub-Committee—an intelligence organization of several nations—to locate and gather evidence for the Nuremberg trials.

Between May and September 1945, Alexander visited numerous concentration camp dispensaries and laboratories used by Nazi doctors; interviewed camp survivors, doctors, and their assistants; and examined detailed medical reports on multiple concentration camps experiments, particularly the infamous Nazi hypothermia experiments conducted by Sigmund Rascher and others at the Dachau, Germany, concentration camp. Alexander thought that none of the participants could have been volunteers, and most of them died from cold exposure. Alexander scrutinized numerous rewarming methods, which Nazi doctors tested on inmates, and commented on their effects on participants. Although he was appalled by these experiments, Alexander could not help thinking that these methods could have some military value, and he even suggested that rapid and intensive rewarming in hot water should be immediately adopted as the treatment of choice by the air-sea rescue services of the US Armed forces. Alexander examined the 1942 high-altitude experiments by members of the German Air Force Division, which described simulated rapid and slow lowering of participants from great heights in a low-pressure chamber. He noted:

These individuals should definitely be tried. Apart from unnecessary infliction of pain, suffering and death upon innocent human beings, it is quite obvious that these doctors failed to add one iota to the information already obtained via animal experiments.

Alexander reviewed the seawater experiments on inmates conducted at Dachau by Wilhem Beiglboeck, which he discussed with the American physiologist Ivy. Alexander noted that German doctors were eager to cooperate with American authorities and discuss their research in detail because they believed American doctors had similar research interests. Any assistance to the United States in accelerating its victory over Japan would also be in the interests of Germany.

In late June 1945, Alexander left for London with volumes of Nazi documents, including letters, graphs, private notebooks, reprints, pamphlets, and microfilm related to the Nazi’s experiments. In September 1945, he submitted detailed reports on his findings to Combined Intelligence Operative Sub-Committee before returning to the United States. Alexander returned to Nuremberg in 1946 as chief medical advisor to the secretary of war and the US chief council for war crimes.

On December 7, 1946, 2 days before the opening of the Doctors’ Trial, Alexander sent General Taylor a memorandum: “Ethical and Non-Ethical Experimentation on Human Beings.” In this memorandum, he identified 3 ethical, legal, and scientific requirements for the conduct of human experiments: (1) moral and legal requirements (obtaining a legally and ethically valid consent from the participant); (2) medical-ethical (Hippocratic) requirements (moral obligation of the investigator toward the participant as described in Hippocratic ethics); and (3) scientific requirements (the quality of the research project). Alexander indiscriminately applied Hippocratic ethics to research and treatment practices.

On April 15, 1947, after reviewing a detailed analysis of the “volunteering” aspect of the American malaria experiments done on prisoners, Alexander submitted to Taylor a second memorandum in which he set forth 6 specific conditions for ethically and legally permissible human experiments, including conditions for a new category of participants, the mentally ill patient. He noted that the ultimate aim of research is “to cure, treat and prevent illnesses” and must not be killing, for which he coined the term “ktenology.” Both memos were consistent with his views on Hippocratic ethics.

Alexander was not called to testify, but his role behind the scenes could be seen as more influential than that of the 2 physician-expert witnesses. In his room, number 221 at the Nuremberg Palace of Justice, he had direct access to the defendants. There, he prepared and reviewed depositions, coordinated testimonies, orchestrated and reviewed hundreds of affidavits, and helped the prosecution assess the harmful consequences on victims of Nazi experiments. Alexander may have advised the prosecution to call on Leibbrandt, a fellow neuropsychiatrist, to testify as the prosecution’s first witness. Alexander was deeply (and rightly) troubled by the role psychiatrists played in the racial hygiene programs of the Third Reich, and by recommending Leibbrandt, Alexander may have hoped to seize a unique opportunity to help rehabilitate the psychiatric profession, returning to it the respect and leadership he thought it deserved.

Werner Leibbrandt

On January 27, 1947, the prosecution called Werner Leibbrandt, a respected medical historian and a neuropsychiatrist, to testify on “the effect of Nazi dictatorship on the German medical profession and medical standards.” Born in 1896 in Berlin, Leibbrandt was persecuted by the Nazis because of his liberal political views and because his wife was Jewish. He was removed from all academic functions and forced to accept a subordinate position as a medical consultant in a psychiatric clinic. There, he saw firsthand the effects of Hitler’s sterilization and extermination programs for the mentally ill, and barely escaped the Gestapo after refusing to conform to Nazi prescribed “treatment.” After the Allied Forces occupied Germany, Leibbrandt was promoted to the directorship of the municipal hospital at Erlangen, Germany, and in May 1946, he was named honorary professor of history of medicine at Erlanger University. He testified in this capacity.

Leibbrandt declared that German culture and medicine at the beginning of the 20th century lacked a sense of morality and reverence for life. He cited a well-respected and internationally known German neuropsychiatrist, Albert Moll, who as early as 1920 had denounced doctors who conducted experiments on patients without their consent. According to Moll, this was symptomatic of a view that human beings were “mere objects” or a “series of biological events” or “mail packages.” Leibbrandt testified that this view originated with the publication in 1920 of an influential book, Die Freigabe der Vernichtung Lebensunwerten Lebens (Permission to Destroy Life Unworthy of Life) by the jurist Karl Binding and the psychiatrist Alfred E. Hoche. These authors coined the concept of “life unworthy of life” that justified its “destruction” as a “healing act” for the health of the German nation. Binding stated that the doctor’s responsibility was to terminate the lives of those who were mentally ill, deformed, or socially useless.

By the time Hitler became chancellor on July 14, 1933, the concept of “life unworthy of life” was widely accepted by the general German public and with it new values on life and death. Soon doctors were permitted to perform involuntary “euthanasia” on those perceived as “useless eaters” and to send them to be killed. Leibbrandt testified that these medical acts were a perversion of Hippocratic ethics, which is to act only in the patient’s best interest. More than a quarter of a million people were sterilized under the “racial hygiene” program, and this was the beginning of the mass extermination of the Jews, Roma, homosexuals, and those perceived as subhuman. Leibbrandt strongly condemned these developments, characterizing them as “an outgrowth of biological thinking where human relationship (i.e., our humanity), no longer existed.” Leibbrandt testified:

The Hippocratic Oath had been the universal legal and moral code of physicians for 22 centuries and had explicitly forbidden causing harm to patients, injustice and immorality. Nazi doctors and SS members who had said they relied on the Hippocratic Oath in their practices were simply grotesque.

On cross-examination, defense lawyers contended that the good of the state must take precedence over individual welfare, and thus “physicians must comply with superior orders for the common good.” Leibbrandt strongly disagreed, stating, “The state may order physicians to conduct illicit experiments on human participants, but physicians remain accountable for their actions.” The Nazi defense then presented evidence that “civilized” nations such as France, Holland, Great Britain, and the United States had used prisoners as participants in dangerous experiments without their voluntary consent, and thus Nazi doctors only followed this unwritten standard of practice. Leibbrandt firmly declared that “any experiment on prisoners is unethical because prisoners are in a forced situation and cannot be volunteers, regardless of what they say or sign.”

The condemnation of prison research was to be applied to the malaria experiments performed in the United States on 800 men incarcerated in various state and federal prisons. This disapproval of an important American experiment by the prosecution’s first witness created a credibility problem for the prosecution. The argument that Nazi doctors were not guilty because they followed ethics consistent with American doctors needed to be skillfully addressed. Reliance on psychiatrists alone was not sufficient. The prosecution had a witness who was an authority on prison research and had wartime research interests similar to those of Nazi doctors. They had Andrew C. Ivy.

Andrew C. Ivy

Born in 1893 in Farmington, Missouri, into an educated family, Ivy was to many scientists and others bigger than life. He was imposing, eloquent, exceptionally gifted, passionate, and a committed scientist—an expert in aviation medicine. He was the vice president of the University of Illinois and had directed the Naval Medical Research Institute in Bethesda, Maryland, from 1941 to 1943. Ivy also had firsthand knowledge of the American malaria experiments at the Statesville Penitentiary in his home state of Illinois, which Nazi defendants wanted to associate with those they had conducted on concentration camp inmates.

Ivy began exploring Nazi medical documents in early 1945, when he was a consultant to the Bureau of Medicine and Surgery of the US Navy. In this capacity, he examined volumes of Nazi experiments, including Dachau hypothermia and high-altitude experiments, and discussed his findings with Alexander (and Thompson) before submitting them with comments on the completeness, reliability, and precision of the collected scientific data. When the secretary of war asked the American Medical Association to nominate a person who understood rules and practices in prison research for the Medical Trial, Ivy emerged as the natural recommendation. On January 27, 1947, Ivy was in the Nuremberg courtroom to hear Leibbrandt inflexibly condemning the American malaria research.

On June 12, 1947, Ivy was ready to begin his own testimony as the only physician-expert on medical ethics to testify in rebuttal for the prosecution. His testimony was the longest of the trial. It was given on June 12 through 14 and June 16, and comprised 295 pages of the official transcript. It was also the most vexing. Ivy’s imposing presence and eloquence delighted the prosecution, but this excitement was not transmitted in the trial’s transcript. Reading the transcript, it would seem that Ivy came to Nuremberg for one reason: to tell the judges (and the world) how research was done in a democratic country by decent, competent, and ethical scientists like himself.

On direct examination, Ivy recounted his inquiries about the conditions under which research on human beings had been conducted in various “civilized” nations. He testified that, as a result of his findings and at the request of the American Medical Association, he had formulated 3 principles that reflected “common agreement and research practices.” These 3 principles were adopted by the American Medical Association House of Delegates in December 1946. The first principle reads: “Consent of the human participant must be obtained. All participants have been volunteers in the absence of coercion in any form. Before volunteering, participants have been informed of the hazards, if any.” The second principle requires the proposed experiment to yield results unprocurable by other means, and the third principle requires the investigator doing the research to be qualified.

In a difficult cross-examination, Ivy had to acknowledge that there were no written research principles in the United States or elsewhere before December 1946 and that the American Medical Association principles were formulated only for the purpose of the Doctors’ Trial. When asked to explain why it was necessary to articulate new ethics principles in addition to Hippocratic ethics, Ivy replied that these new principles were necessary for addressing “modern conditions, but the basic [Hippocratic] principles have eternal validity [and] have not been altered…. The Oath teaches a fundamental basic truth that is good for all time, namely reverence for life.”

The defense counsel then raised questions about the extensive use of prisoners as participants in dangerous experiments and cited Leibbrandt, who had said that this was unethical. Ivy replied that he strongly disagreed with Leibbrandt:

Being a prisoner created no unique ethical problems because prisoners can be volunteers…. Volunteering occurs when a competent person says “yes” or “no” without fear of being punished or deprived of privileges due him in the ordinary course of events. And prisoners can do that…. Our experience with prisoner-volunteers in the United States shows that it can be done.

Ivy did not object to enrolling prisoners as subjects in dangerous experiments. His only objection concerned whether the participants gave consent. He stated:

The American malaria experiments with 800 prisoners were absolutely justified, scientifically and ethically even if they bring with them danger to human life. To treat malaria was an important scientific problem, and so long as the participants volunteer and are explained the hazards of the experiments, there is no ethical reason against it…. If prisoners condemned to death are volunteers, then it was ethical to do just that.

When asked whether conducting dangerous experiments on prisoners who are asked to waive their rights to all claims for themselves and their heirs conformed to medical ethics, Ivy replied that this can be reconciled with basic medical ethics. Ivy, however, could not justify state orders that would require physicians to do harmful experiments on death row prisoners, even if it were to “save lives.” Ivy explained:

In such cases prisoners would not be volunteers. Physicians should only be guided by their own conscience and the moral ideals of their profession. There is no justification in killing five people in order to save the lives of five hundred…. There is no state or politician under the sun who could force me to perform a medical experiment which I thought was morally unjustified.

Asked about the ability of participants to drop out of an experiment before its conclusion, particularly in the malaria (or typhus) experiments, in which participants were infected as part of the protocol, Ivy replied that this was not possible in the case of malaria but is generally permitted. Taking himself as an example, he declared:

I have always permitted volunteer subjects to withdraw from the experiment whenever they expressed the desire to do so [because]… if I forced a subject to continue the experiment he would not be dependable and cooperative and I could not expect to obtain valid data from him… and also because of humanitarian and pragmatic, ethical philosophy.

What Ivy meant by “humanitarian and pragmatic, ethical philosophy” is difficult to know. But his emphasis on efficiency and the pragmatic aspect of the participant’s right to withdraw rather than on its ethical quality may have prevented him from recognizing that participants have a moral and legal right to make their own decisions about withdrawal independently from the investigators—a point that the voluntary aspect of the consent did not address. Put differently, permitting volunteer subjects to withdraw from an experiment when they expressed such a desire is not the same as saying they have the unconditional right to withdraw—a subtlety that probably escaped Ivy.

Finally, Ivy was asked to reconcile the Hippocratic maxim that forbids giving lethal poison to patients even if they ask for it, with the research proposition that justifies giving poison to volunteer participants in dangerous experiments. Ivy replied (probably unaware of the implication), “I believe that refers to the function of the physician as a therapist, not as an experimentalist and what refers to the Hippocratic Oath is that he must have respect for life and the human rights of his experimental patients.” Ivy repeatedly said that he relied on Hippocratic ethics, which govern the doctor-patient relationship. In the end, however, he folded, undermining his entire testimony, which was intended to demonstrate the relevance of Hippocratic ethics to human experimentation. He had to admit that there were differences between a treating physician who acts in his patients’ best interests and a physician-investigator whose goal is to test a scientific hypothesis for the benefit of society rather than the participant.

In his closing argument on July 14, 1947, the chief prosecutor, James McHaney, highlighted what Ivy repeatedly reiterated in his testimony:

If the experimental subjects cannot be said to have volunteered, then the inquiry need proceed no further….This requirement reflects not just the view of an individual or of an American doctor, but the opinion of all medical men, and decent people of the civilized world.

In their judgment, the Nuremberg judges articulated 10 research principles (the Nuremberg Code) centered on the rights of participants and not on the rights of doctors. The Code goes beyond the Hippocratic physicians’ obligation to protect the life and welfare of their patients-participants by stating that participants have explicit rights and the authority to protect themselves. These are the right to voluntary, competent, informed, and understood consent (principle 1) and the right to withdraw from an experiment before its conclusion (principle 9). Both are necessary for self-protection (autonomy) and human dignity (integrity) in human experimentation.

The Aftermath of Nuremberg

Alexander and Ivy believed that being a Hippocratic physician embodied virtue, trust, and the highest moral ideals. As a result, these physicians did not seem to appreciate the monumental shift the Nuremberg Code represented, particularly the introduction of moral rules centered on the participant and not on the physician. For example, Alexander thought the Code was “merely a refinement” of his own 1947 memorandum, and he relentlessly claimed that he was the original author of the Code. Ivy, too, claimed “virtually exclusive authorship almost 20 years after the fact.”

Both Alexander and Ivy also conflated research with treatment even after Nuremberg. Alexander shockingly mischaracterized horrendous Nazi medical research as therapeutic, that is, as benefiting the participant-patient. Examples include the typhus and hypothermia experiments about which Alexander remarked:

It is often assumed that the war crime court concerned itself only with non-therapeutic experiments. This is certainly not the case, since the exposure to cold experiments, for instance, had a therapeutic aspect as did the typhus experiments and others. The only difference is that the predicament to be solved therapeutically had been produced as part of the experiments and was not a naturally occurring disease.

There was, of course, no therapeutic intent directed at the participants in any of these brutal and fatal experiments by Nazi doctors. But because Alexander conflated research with treatment, he did not (and perhaps could not) see the profound difference between experimenting (testing a hypothesis) on participants and treating patients (in their best interests), and as a result he was able to rationalize his own experimental work as “benefiting patients.” Reliance on Hippocratic ethics permitted Alexander to do research on human beings that he would not have been permitted to do under the Nuremberg Code. During the war, for example, he experimented on British pilots without their consent, believing that it would benefit them and insisting that no rules should interfere with decisions the Hippocratic physician makes for his patient-participants: Hippocratic physicians could do no wrong.

In 1973 Alexander sent a letter to the New England Journal of Medicine questioning the applicability of judge-made ethics rules like the Nuremberg Code to his own research. He used the Nuremberg War Crimes Trial (the so-called Big Trial) to stand for the proposition that doctors should not be compelled to follow the laws of the state. He was particularly dismayed that the state of Massachusetts had limited the number of electroconvulsive treatments a psychiatric patient could get in a calendar year to 35, a rule designed to protect the rights and welfare of psychiatric patients. He wrote, “Such temporal laws, in comparison to our Hippocratic obligation, enduring throughout the entire history of medicine, are merely words into sand.”

Alexander remained at the center of controversy during his entire professional life. He died in a nursing home in Newton, Massachusetts, on July 20, 1985, at the age of 79. His obituaries almost uniformly read that he wrote the Nuremberg Code.

Ivy also refused to consider the Nuremberg Code as an authoritative ethical and legal document meant to be universal. He wanted no interference with decisions Hippocratic physicians make in conducting research. Because the Code was linked with Nazi atrocities, it was easy to marginalize it. A reasonable response to the Nazi medical crimes seemed to be that they were extreme aberrations that would never be performed by Hippocratic physicians. In Ivy’s mind, being a Hippocratic physician was all that was needed to really protect participants in human experimentation. Ivy, of course, also made the mistake of equating research and treatment: for him both were meant to benefit patients.

Consistent with this belief, Ivy spent most of his post-Nuremberg professional time promoting an investigational drug, which he mischaracterized as an anticancer drug: Krebiozen (a substance taken from the reticuloendothelial system of a horse and separated from the serum by a chemical process). He treated his cancer patients as if they were research participants, while at the same time administering an experimental agent he believed was treatment. After multiple studies, Krebiozen was found to have no curative or palliative value, and it was widely viewed as quack medicine. Ivy’s obsession with Krebiozen caused him to resign his position as vice president of Illinois University in 1953. He continued to work on this drug at his own expense at the Ivy Cancer Institute until he died in 1976.

Leibbrandt resumed his seminars on the history of medicine and philosophy. A member of several international organizations, he understood the importance of education and never missed an opportunity to reflect on what had happened to German medicine under the Third Reich, particularly to the psychiatric profession. He settled in Munich in 1953 as the director of the Institute of the History of Medicine at the Ludwig-Maximillian University of Munich and coauthored several books on medicine. He died in Berlin in 1974.


On the 70th anniversary of the Doctors Trial, it is worthwhile to remember the physicians who helped the American judges write the Nuremberg Code. By shifting their emphases away from the victims of Nazi medical atrocities, the judges were able to make room for the Code—an important historical document that requires medical researchers to treat study participants as human beings with rights and dignity. In doing so, the judges proclaimed that Nuremberg, “a place of evil,” was also “a place of justice.” The victims’ hellish experiences must remain in our collective conscience.