Gallstone disease (cholelithiasis) affects 15-20% of the Western civilization and causes an enormous economic burden. The formation of gallstones is very complex and is influenced by multiple risk factors. Diverse mechanisms are discussed as possible pathogenic elicitors. Our study group analyzes the regulative factors of the bile acid transport in the terminal ileum (part of the small intestine). We could show that female normal weight gallstone carriers exhibit a diminished expression of all investigated bile acid transporters in contrast to healthy controls. Our recent investigations comprise the genetic background of this reduced expression with respect to possible genetic alterations in association to cholelithiasis. Another risk factor for gallstone development is a disturbed cholesterol homeostasis. Here we focus our research on the expression of the intestinal cholesterol transporters. Our aim is to contribute to the elucidation of the various mechanisms of gallstone disease in diverse risk groups.