[Gallstones: etiology and risk factors]

Cholesterin is excreted into bile together with phospholipids and bile acids, which are essential for the formation of micelles. Cholesterin-supersaturation of the bile and a relative hyposecretion of bile acids, the presence resp. the lack of promotors and inhibitors of nucleation and a reduced gallbladder contractility are the most important factors in the formation of cholesterol stones. For the formation of pigment stones, however, an increase of bilirubin production and infection of the biliary tract are the causative factors.