It has long been implicated in disease of the gall-bladder particularly in the pathogenesis of cholelithiasis. Gallbladder disease occurs with increased frequency in hypercholesterolemic states. There is little precise information, however, on the metabolic abnormalities which are responsible for the formation of gallstones. Bile contains cholesterol and cholesterol is metabolized to bile acids. The gallbladder wall can absorb lipids and cholesterol deposits are common in the wall and lumen of the gallbladder, increasing with advancing age. Aside from these few facts, little is known of the role of cholesterol in the production of cholelithiasis. The current extensive investigation of lipid metabolism should elucidate this problem.