Symposium—Some Recent Advances in Hepatobiliary Disease and in the Clinical Aspects of Bile Acids

are misleading and likely to lead to faulty ideas in attributing both etiologic causes to the stones, and potential for succesful dissolution. It is now generally agreed that all stones in gallbladders harboring multiple stones are of approximately the same composition. Further, if one plots percent of patients undergoing elective cholecystectomy for biliary pain, but without complications (i.e. no infection) versus per cent cholesterol in a single stone obtained from each gallbladder, one obtains a bimodal frequency distribution nomogram. In Western countries approximately 25% of gallstone patients have stones with <30% cholesterol by weight?most with <10% cholesterol. These are pigment gallstones and are composed of amorphous calcium bilirubinates that have undergone polymerization and oxidation, calcium carbonate and less frequenly calcium phosphate. Provided the bile is sterile and the stones contain no evidence of previous bacterial infection of bile (e.g. absence of bacterial rhamnose), no