We have collected gastric and duodenal drainage in five mongrel dogs. During the administration of secretin and pancreozymin, parenteral hyperalimentation significantly decreased the volume of duodenal fluid by; 50.5%; excretion of bilirubin by 86.2%; secretion of amylase by 70.8%; content of protein in duodenal fluid by 73.1%; and increased bicarbonate concentration in duodenal fluid by 18.2%. The P values for the reductions in duodenal fluid volume and amylase were much less than 0.0005. No uniform change in gastric secretory volume or pepsin occurred. Parenteral hyperalimentation promotes healing of high enterocutaneous fistulas by producing positive nitrogen balance. In addition, it favors healing of such fistulas by decreasing the volume and modifying the content of digestive secretions. By virtue of the later effect, parenteral hyperalimentation may be beneficial in the management of other upper gastrointestinal tract, biliary, and pancreatic diseases.