Objectives. - Endoscopic sphincterotomy has become a generally accepted method for extracting common bile duct stones in high risk or cholecystectomized patients. However, stone extraction is impossible by the usual methods in 5 to 10 % of cases. The purpose of this study was to evaluate the effect of a recently developed solvent system in patients with large bile duct stones. Methods. - Forty four patients (15 men and 29 women, median age 61 years) underwent contact dissolution after unsuccessful Dormia extraction. Solvents were administered via a nasobiliary catheter in 41 patients following papillotomy and through a T-tube in 3 patients. Solvent mixtures (26 mM ethylene diamine tetraacetic acid, 40 mM sodium deoxycholate and 30 % dimethyl sulfoxide in an alkaline aqueous solution; and a 70/30 dimethyl sulfoxide/methyl tert-butyl ether mixture) were infused continuously and alternatively for 2 hours. Results. - Bile duct stones disappeared in 13-24 hours of infusion in 11 patients. In 29 patients, a clear reduction in stone volume occurred, allowing complete endoscopic extraction of the fragments. In 4 patients, the size of the stone did not change. Only mild and transient side-effects including abdominal pain (68 %), nausea (72 %), vomiting (52 %), diarrhea and sleepiness (50 %) were observed. Conclusion. - Direct dissolution therapy could be all effective method for the non-surgical management of large bile duct stones in selected patients when intra- or extracorporeal lithortripsy is unsuccessful.