Two hundred and twenty patients with a total of 412 gall bladder stones of between 8 and 38 mm in size were treated with extracorporeal shock wave lithotripsy, using the overhead module Lithostrar Plus. Fifty six per cent of stones were solitary (mean (SD) diameter 23 (5) mm) and 9.5% of the patients had more than three stones. Stones were successfully disintegrated in 218 patients (fragmentation size less than 5 mm in 80%, less than 10 mm in 19%). Some 65% of patients required one treatment and the rest two or three. A mean (SD) of 4100 (1800) shock waves with a pressure of 700 bar were applied. Twenty four to 48 hours after lithotripsy a transient but significant increase in serum transaminase activities (31%) and in bilirubin (29%), urinary amylase (27%), and blood leukocyte (62%) values was observed. In 29% of patients there was a transient microhaematuria, in 2% transient macrohaematuria, and in 25% painless petechiae of the skin. Ultrasound showed temporary gall bladder wall oedema in 13%, temporary distension of the gall bladder in 11%, and transient common bile duct distension in 8% after treatment. After discharge from hospital, 31% of patients complained of recurrent colic that responded to simple analgesics. Four to eight weeks after therapy, four patients developed biliary pancreatitis and 11 biliary obstruction that was managed by endoscopy. To date, 105 patients have been followed for over 12 months. Sixty one of these had a solitary stone, 17 had two, and 27 had three or more stones. A total of 59 patients, including 44 with a primary solitary stone, eight with two stones, and seven with three or more stones are completely stone free.