Aim. To study the role of biliary acids (BAs) in the pathogenesis of chronic diarrhea (CD) in patients undergoing cholecystectomy (CE). Subjects and methods. Twenty-five patients with post-CE diarrhea were examined. A comparison group consisted of 11 patients with diarrhea-predominant irritable bowel syndrome (IBS). The results of an examination of 15 healthy individuals were taken as normal values. Daily fecal BAs were determined by an enzyme spectrophotometric technique. Results. In the patients after CE, daily fecal BA losses were found to be thrice as large as that in the healthy individuals. In the comparison group of patients with IBS, fecal bile excretion was not greater than the normal values. Stool normalization with a simultaneous decrease in fecal BA losses was seen in 92% of the post-CE patients receiving a course of therapy with adsorbents and astringents. Conclusion. Post-CE CD is a type of postcholescystectomy syndrome.