If peptic ulcer surgery favors the formation of carcinogenic N-nitroso compounds in the gastric remnant, an increased risk of cancer at sites in the gastrointestinal tract distant from the stomach might be predicted. To estimate the risk of carcinomas in the digestive tract, other than the stomach, occurring after partial gastrectomy, we analyzed an Amsterdam cohort of 2,633 post-gastrectomy patients operated on for benign disease between 1931 and 1960. Mortality in the study population was compared with the general Dutch population through person-year analysis. An excess mortality of biliary tract cancer (O/E:2.64; CL:1.32-4.72; p less than 0.01) and pancreatic cancer (O/E:1.65; CL:1.06-2.44; p less than 0.05) was found in males more than 5 years after surgery; females showed only an increased risk of pancreatic cancer in the first 5 years postoperatively (O/E:15.33; CL:1.85-55.43; p less than 0.01), probably due to misdiagnosis. All other non-gastric sites of the digestive tract carried no increased risk for cancer. In males, mortality due to colorectal cancer more than 5 years post-operatively was significantly decreased (O/E:0.58; CL 0.34-0.92; p less than 0.01). The excess mortality of biliary-tract and pancreatic cancer in males, which increases with the duration of post-operative interval, is consistent with a dose-response phenomenon. This study therefore supports the hypothesis that carcinogens are not only locally activated in the gastric remnant, but are hepatically excreted and initiate cancer in the biliary tree and pancreatic duct. Further exploration of this mechanism of carcinogenesis is warranted, since it may also explain the pathogenesis of pancreatic and biliary cancers in patients without gastrectomy.