Acute cholecystitis is the most common complication of cholecystolithiasis. With some 64,000 patients per year requiring surgical inpatient treatment it remains a prevalent surgical disease. The presentation varies between mild, severe and life-threatening forms and predominantly in old and morbid patients. Gallbladder perforation is a possible complication which is often only diagnosed during surgery. Typical clinical symptoms are pain in the upper abdomen, fever and leucocytosis. Ultrasonography may often be used to confirm the clinical diagnosis.