The possibility that intraluminal bile acid concentrations contribute to fluid and electrolyte movement in the normal ileum, and that alterations following ileostomy aid ileostomy adaptation, was investigated. A significant correlation between the concentration of chenodeoxycholic acid plus deoxycholic acid, and volume flow through the normal ileum and ileostomy effluent volume was found. The regression lines relating bile acid concentrations to volume flow in the 2 groups were clearly separated, indicating that factors aside from altered bile acid metabolism are predominant in ileostomy adaptation.