Background and purpose: Gallstone is one of the most common problems of hepatobiliary system. Laparoscopic cholecystectomy is a gold standard treatment for this problem. Carbon dioxide (CO2) insufflated in the abdomen for better exposure in laparoscopic cholecystectomy could increase the liver enzyme levels. The goal of this study was to assess the effect of different CO2 pressure (12-16 mm Hg)...