The liver produces bile, a greenish yellow, thick, sticky fluid. Bile aids digestion by making cholesterol, fats, and fat-soluble vitamins easier to absorb from the intestine. Bile also helps eliminate certain waste products (mainly bilirubin and excess cholesterol) and by-products of drugs from the body.

The biliary tract consists of small tubes (ducts) that carry bile from the liver to the gallbladder and then to the small intestine. The gallbladder is a small, pear-shaped sac located beneath the liver. It stores bile (see Biology of the Liver and Gallbladder: Gallbladder and Biliary Tract). When bile is needed, as when people eat, the gallbladder contracts, pushing bile through the bile ducts into the small intestine.

The flow of bile can be blocked by the following:

• Gallstones that pass out of the gallbladder into the ducts
• Injury to the bile ducts during gallbladder surgery
• Disorders of the pancreas, which can narrow the bile ducts that pass through the pancreas
• Tumors in the pancreas or bile ducts
• Infestation by parasites (in Asia)

If the bile ducts are blocked, the gallbladder may become inflamed.

Last full review/revision December 2007 by Eldon A. Shaffer, MD