While Nazism is almost universally recognized as a great evil, control of science and medicine by the totalitarian Nazi state might be viewed as increasing efficiency. Scientific methods are applied to semiquantitatively analyze the effects of Nazism on medical progress in gastroenterology to document its pernicious effects, and to honor outstanding gastroenterologists persecuted or murdered by the Nazis. This is a retrospective, quasi-case-controlled study. To disprove the null hypothesis that Nazism was efficient, retarded progress in gastroenterology is demonstrated by (1) enumerating the loss to Nazi Germany from 1933 to 1944 due to violent death, incarceration, or forced exile of key researchers in gastroenterology, defined by authorship of at least one book or 10 articles in peer-reviewed journals or other outstanding scholarship; (2) demonstrating a statistically significantly greater loss in Nazi Germany than in non-Nazi (Weimar German Republic from 1921 to 1932) or anti-Nazi (democratic America from 1933 to 1944) control groups; and (3) demonstrating that each loss was directly due to Nazism (murder, incarceration, or exile due to documented threat of violence/death or revocation of medical license). Sources of error in analyzing events from 70 years ago are described. Nazi Germany and Nazi-occupied Europe gained 0 and lost 53 key gastroenterology researchers, including 32 lost due to forced exile, 11 murdered by the Nazis, 5 lost due to suicide under threat of violence, 3 in hiding from the Gestapo, and 2 for other reasons. Fifty-two of the gastroenterologists were persecuted solely because they were Jewish or of Jewish descent and one because he was a Christian anti-Nazi Polish patriot. Particularly severe losses occurred in endoscopy. The loss in Nazi Germany from 1933 to 1944 was significantly greater than that in non-Nazi Germany and Austria from 1921 to 1932 (53 versus 4; odds ratio = 25.27; 95% CI: 9.01-70.48; P < 0.0001) and was significantly greater than that in anti-Nazi America from 1933 to 1944 (53 versus 0; odds ratio > 104.0; 95% CI: 17.62-608.95; P < 0.0001). Lost physicians in Nazi Germany (with reasons for loss) included Ismar Boas, the father of modern gastroenterology (suicide after medical license revoked); Hans Popper, the father of hepatopathology (fled impending arrest); Rudolph Nissen, the father of antireflux surgery (fled after job dismissal); Rudolph Schindler, the father of semiflexible endoscopy (fled after incarceration); Heinrich Lamm, the first to experimentally demonstrate fiberoptic transmission and the first to suggest its applicability for gastroscopy (fled after medical license revoked); Hermann Strauss, a pioneer in rigid sigmoidoscopy (suicide in a concentration camp); A.A.H. van den Bergh, who discovered the van den Bergh reaction to differentiate indirect from direct bilirubin (died in hiding in Nazi-occupied Holland); and Kurt Isselbacher, subsequently the Chief of Gastroenterology at Harvard Medical School (fled in childhood after a grandfather murdered by Nazis...