Bile salts facilitate the formation of micelles for fat absorption. They are the product of conjugation of bile acids with taurine or glycine.
Bile acids can be divided into those made in the liver - primary forms - and those derived from primary bile acids by the action of gut bacteria - secondary forms.
Primary bile acids are transported into the biliary tree by carrier-mediated passive diffusion. They are passed to the gallbladder where they are concentrated and stored within bile. On gallbladder contraction, the bile salts pass into the duodenum.
The majority of bile salts are reabsorbed within the gut for recycling back to the liver - the enterohepatic circulation.
Excessive amounts of bile salts within the blood can lead to the symptoms of pruritus.