BACKGROUND Visceral pain is characterized by poor pain localization and a referred or radiating pain pattern. Its clinical importance in the abdomen is stressed by the finding that about one-third of patients still complain of abdominal pain after cholecystectomy. A better understanding of symptoms arising from the gallbladder and the underlying pathophysiology is therefore desirable. The aim of the present study was consequently primarily to characterize the symptom patterns after distension of the gallbladder. Secondary aims were to describe the pressure-volume relation in the gallbladder and the cystic duct opening pressure. METHODS Twelve patients (nine women, three men) treated with cholecystostomy for acute cholecystitis were investigated. Simultaneous cholescintigraphy and measurement of changes in intraluminal gallbladder pressure after injections of saline through a gallbladder catheter were performed. After each injection of saline the localization of pain and the presence of nausea and vomiting were registered. The injections continued until the patient felt abdominal pain necessitating cessation of the investigation or until the cystic duct opened (visualized on cholescintigraphy). RESULTS Distension of the gallbladder caused pain in 10 of the 12 patients. In 70% the pain was localized under the right costal margin or in the epigastrium. No mathematical formula could describe the pressure-volume relation in the gallbladder. The cystic duct opening pressure varied between 3 and 44 mmHg. CONCLUSIONS Pain caused by increased gallbladder pressure is localized mostly, but not always, under the right curvature and in the epigastrium. A substantial variation in cystic duct opening pressure was found.