The aim of this study was to investigate whether the cathartic effect of chenodeoxycholic acid (CDCA) could be helpful in the management of chronic constipation. Twenty cholesterol gall-stone patients with chronic constipation were randomly treated with either CDCA (750 mg/day in three divided doses at meals) or placebo for a period of 4 weeks. The administration of CDCA produced a significant increase of stool frequency and a decrease of stool consistency, while placebo was not effective in improving the bowel habit of the patients. As some patients complained of diarrhoea, and some had no modification of bowel frequency, further studies are needed to determine the most appropriate dose for each patient.