Pancreatic exocrine responses to oral and intraduodenal administration of an elemental diet and to an i.v. administered hyperalimentation solution were determined in dogs with fistulas of the stomach and pancreas. Administration of an intraduodenal elemental diet prevented the responses to H2O and CO32- seen with oral administration but did not prevent the protein response. I.v. administered hyperalimentation solution produced only minor effects on pancreatic secretion when compared with the elemental diet.