Retained common duct stones can now be treated by a number of non-operative techniques, including dissolution by cholesterol solvents, simple irrigation, stone extraction via the T tube tract and by endoscopic sphincterotomy. This paper reviews the various solvents available for stone dissolution and its physicochemical basis. When a retained stone is found simple irrigation with saline will be successful in about 50 per cent of patients. If this fails, stone extraction via the T tube tract or by endoscopic sphincterotomy are now the methods of choice, with a 90–95 per cent chance of success. Stone dissolution by cholic acid is slow and is only successful in about 60 per cent of patients but can be of value when stone extraction is unavailable or unsuccessful.