The primary purpose of bile in the digestive process is to facilitate the digestion and dispersion of consumed fats. According to the Encyclopedia Britannica, this takes place in the lumen of the small intestine.
Bile is a digestive fluid made up of electrolytes, water and organic molecules such as cholesterol and bile acids, as noted by About.com. Bile acids have an emulsifying ability that breaks down lipids, and they also work as lipid carriers to transport fats through an aqueous environment. In addition to aiding the digestion of fats and fat-soluble vitamins, bile helps to eliminate waste products from the body. For instance, approximately 500mg of cholesterol is converted into bile acid each day, which is then eliminated in the feces.
The Encyclopedia Britannica states that bile begins forming in the liver cells, and its rate of formation is largely dependent on the secretion of bile acids into the body's bile channels. Roughly 3 grams of bile acid is present in the body at any one time, and most of this pool is in the gallbladder where bile is highly concentrated. When a person consumes a meal that includes fat, a hormone is released that causes the gallbladder walls to contract, releasing bile into the digestive system.