A novel, totally implantable catheter system that allows complete bile collection and duodenal access in conscious, freely moving dogs is described. Bile collection catheters remained patent for an average of 417 days (range, 711010 days) in eight animals which were used on study. Three animals have been used to validate the models complete collection of bile via biliary recovery of an intravenous dose of 14C-glycocholic acid, and in selected animals, parameters potentially indicative of liver damage (serum alanine aminotransferase, alkaline phosphatase, gamma glutamyltransferase, and total bilirubin levels) were within normal ranges for as many as 14 months after surgery. The eight study dogs have been used in a total of 29 studies, in which bile was successfully collected for 1248 h. The bile has been collected by using either a tethering system or a protected pouch arrangement. Compared to exteriorized catheter techniques, this system requires less maintenance and is better tolerated by the animals. The potential for a longer functional life span for individual animals, more normal liver enzymes, and the capability to selectively infuse towards the duodenum and flush the entire catheter and bile duct are other advantages of this model.