The majority (80–90%) of gallstones formed within the gallbladder consist mainly of cholesterol (70%) in a matrix of bile pigments, calcium salts and glycopro- teins [73] (Fig. 2). Besides pure and mixed cholesterol stones, also pure pigment stones are found. Brown pigment stones are associated with infections of the biliary tract (bacterial and helminthic deconjugation of bilirubin glucuronides) and are more frequent in Asia. Black pigment stones mainly consist of calcium bilirubinate and are found in haemolytic anaemia or ineffective haematopoiesis and in patients with cystic fibrosis [74]. Increased enterohepatic cycling of biliru- bin is the suggested cause of black pigment stones [75], also in patients with ileal dysfunction consistent with the finding of high levels of bilirubin in bile in patients with active ileal Crohn’s disease or after ileal resection [76–79]. However, in these patients with bile salt malabsorption, other factors leading to biliary cholesterol supersaturation [78, 80] may preferably promote cholesterol gallstones.