Because of the in a controversial way held discussion on an possibly existing connection between bile acid metabolism and the development of colonic carcinomas experimental researches on this problems were carried out with Wistar rats. Two test series with altogether 130 animals manifested independently from each other the result of a provable connection. During model tests small bowel resections and colon exclusion operations were realized. The carcinoma protection was accomplished by 1.2 dimethylhydrazine administered for 14 weeks in a doses of 20 mg/kg body weight. The carcinoma was proved after a 32-weeks-period. It was shown that in case of shortening the ileum more than in case of reduction of the jejunum on the left-side colon adenocarcinomas develop and the amount of the excreted fecal bile acids is the highest one. In bypassing the left-side section of the colon carcinomas develop also on the left side of the colon. But their number is significantly lower than of those on the right side. The test results indicate a causal connection.