At Baylor University Medical Center in Dallas, we began performing lithotripsy with the Medstone STS lithotripter for gallstones in January 1988 and in the first year treated 81 patients. Fifty-five of these patients were available for 4-month follow-up. We randomized half of the patients to receive ursodeoxycholic acid for 7 days prior to lithotripsy and gave all of the patients ursodeoxycholic acid after lithotripsy. Only 10.4 percent of the patients who contacted us ultimately proved to be candidates for lithotripsy. Gallstone fragmentation occurred in 95 percent of all patients and in 97 percent of those patients with solitary stones under 20 mm in size. The rate of clearance for solitary stones less than 20 mm in size was 50 percent. Unfavorable effects ascribable to lithotripsy were infrequent. All of the patients had pain before treatment, and one-third complained of biliary colic after treatment. Minor skin bruising which resolved in 1 to 5 days was found in 20 percent of the patients. This study lends credence to the findings of previous studies and demonstrates that lithotripsy combined with bile acid therapy is a useful therapy for cholelithiasis.