Thirty patients with chronic upper abdominal pain and no evidence of cholelithiasis were entered into this study. All had negative ultrasonography of the gallbladder, and most had a host of other negative investigations. These patients were referred to a surgeon to evaluate the possibility of atypical biliary colic associated with chronic acalculous cholecystitis. All patients underwent cholecystokinin-stimulated cholescintigraphy and were offered cholecystectomy if the ejection fraction was less than 35 per cent. Of the 30 patients, 27 (90%) had pathologically abnormal gallbladders. Follow-up averaged over 1 year (13.2 mo), and relief of symptoms occurred in 28 (94%). The authors conclude that in appropriately selected patients with symptoms of biliary colic (typical or atypical) and no evidence of cholelithiasis, a cholecystokinin-stimulated cholescintigram is a significant help in predicting not only which patients have gallbladder disease, but also how likely cholecystectomy is to result in an improvement in their symptoms.