Binds to bile acids and is involved in enterohepatic bile acid metabolism. Required for efficient apical to basolateral transport of conjugated bile acids in ileal enterocytes (By similarity). Stimulates gastric acid and pepsinogen secretion (By similarity). Predominantly expressed in ileum; also expressed in ovary. Forms a beta-barrel structure that accommodates hydrophobic ligands in its interior. Can bind at least two ligands per molecule, however, the stoichiometry is debated. Belongs to the calycin superfamily. Fatty-acid binding protein (FABP) family.