Critical review of cholescintigraphy in critically ill patients suggests the examination will not conclusively prove or disprove the diagnosis of acute cholecystitis. Of 17 scans performed in critically ill patients with clinical evidence of acute cholecystitis, 7 were true-negative, 1 was false-negative, 6 were false-positive, and 3 were nondiagnostic. Cholestasis and hepatocyte dysfunction, common in the critically ill, result in abnormal clearance of hepatobiliary radionuclide imaging agents, decreasing the usefulness of cholescintigraphy in this patient population. Diagnosing acute cholecystitis in a critically ill patient remains difficult.