Five cases of retained bile duct stones treated with heparin in normal saline are reported. In 2 cases the stones were retained in the left hepatic duct, proximal to the T tube. Infusion of heparin in normal saline was found to be simple and effective in treating retained bile duct stones without obvious side-effects. If stones are inadvertently left in the common bile duct following surgery, attempts should be made to encourage them to pass by heparin infusion through the T tube before a second operation is contemplated. Sufficient time must be allowed before the treatment is considered to have failed.