The effects of truncal vagotomy and selective gastric vagotomy on the conjugated bile acids and rations T/G and Tri/Di have been studied in twenty dogs. The results show that truncal vagotomy has no effect on the conjugated bile acid values determined in the 4th and 16th week. The ratio T/G increased while the Tri/Di decreased in the 16th week. The selective gastric vagotomy only shows a change of the taurocholic acid levels which are lower than the control levels in the 4th week.