Bile acids travel along the gut-liver axis in a perpetual and efficient cycle, with minute proportions that leak into the systemic circulation or are excreted in feces. In the hepatocytes, primary bile acids are synthesized from cholesterol (Flag 1). After conjugation to taurine or glycine, highly soluble conjugated bile acids are secreted at the biliary pole of the hepatocytes into the bile (Flag 2). Bile acids then reach the gut lumen, where they interact with a wide range of gut microorganisms and undergo transformations by microbial enzymes to yield secondary bile acids (Flag 3). The majority of bile acids are reabsorbed into the portal circulation (Flag 4) that carries them back to the liver where they are recaptured by the hepatocytes (Flag 5). These five steps along the enterohepatic cycle offer five possible targets for therapeutic interventions.