This case report compares the pancreatic output with different feeding regimes in a patient who underwent a partial pancreatectomy for carcinoma of the ampulla of Vater. A postoperative secretin stimulation test demonstrated significant pancreatic reserve. There was no difference in pancreatic exocrine secretion when the patient was fed jejunally with a polymeric immune-enhancing formula or supported with two different formulations of total parenteral nutrition. This result suggests that jejunal infusion of a polymeric immune-enhancing formula may be safe to administer in patients with acute pancreatitis.