Today, nearly 90% of common bile duct stones are extracted endoscopically. Problems are encountered if there are large stones or a duct stenosis. Extracorporeal piezoelectric lithotripsy (EPL) as well as intracorporeal electrohydraulic lithotripsy (EHL) serve as an alternative to surgical intervention for those few patients in whom endoscopic measures have failed. A total of 35 patients with common bile duct stones in whom conventional endoscopic treatment had failed were selected on the condition that stone visualization through ultrasound was possible and that the papilla was within easy reach of the endoscope. Patients fulfilling the inclusion criteria were randomly treated either by EPL or EHL. The average age of our patients was 73 years. The main reasons for failure of conventional endoscopy were due to the large size of the stones (13 patients), impacted stones (16), or the presence of a biliary stricture (6). In the EPL group, visualization of the stones by ultrasound and ensuing treatment were possible in 16 of 18 patients (89%); stones could be fragmented in 15 patients. In 13 patients, the biliary tree could then be completely freed of calculi; the success rate was 72% for all the patients (13 of 18). On average, the patients had 2.3 treatments on the lithotripter, and 3870 shock waves were applied per treatment. In the EHL group stones were successfully fragmented in 13 of 17 patients (76.5%). The average number of treatments was 1.4. Comparing both therapies, there was no difference in stone-free rates. In both groups, additional endoscopic interventions were necessary to clear the bile duct.(ABSTRACT TRUNCATED AT 250 WORDS)