To investigate the possibility that bowel-related liver disease is due to accumulation of abnormal bile acids in the enterohepatic circulation, bile acids have been measured in gall-bladder bile and portal blood of patients with chronic bowel disease, none of whom had liver disease. There was no difference in the composition and concentration of bile acids in bile and portal blood compared with control patients. In a second study, serum bile acid composition and concentrations were similar in two groups of patients with liver disease, whether they had bowel disease or not. In a further study, post-prandial serum bile acid concentrations were not elevated in a group of patients with chronic bowel disease, making it unlikely that subclinical liver disease was present. No evidence has been found to support the hypothesis that bowel-related liver disease in man results from the action of abnormal bile acids. © 1977 S. Karger AG, Basel.