Results from biliary fistulas indicate that from 600-700 cc. bile are secreted daily. Bladder bile consists of 11% total solids, 6% bile salts, 0.357% cholesterol, while fistula bile consists of 1.92% total solids, 0.715% bile salts, and 0.05% cholesterol. Thus concentration occurs in the bladder. Percentage of bile salts in bile does not decrease when bile escapes through fistula, hence bile salts are not an absorption product. Most of the excreted coprosterol comes from diet, but some is derived from bile cholesterol. The bulk of bile cholesterol passes into the feces although cholesterol is better absorbed than coprosterol. Cholesterol and cholic acid must have synthetic origin, perhaps a common one. That bile is not necessary for health is shown by animals with a biliary fistula.