The results of intubation tests on 50 patients before and after gastrectomy have been reviewed. Following gastrectomy, the pancreatic response to food is modified in the following manner.(1) There is an increase in the resting volume of secretion.(2) After a Billroth I operation, the output in one hour after a meal is some two-thirds of the pre-operative output.(3) After a Polya gastrectomy, the pancreas continues to secrete at its resting rate after meals.(4) Dissociation of enzymes occurs in the afferent loop after a Polya operation. Lipase is frequently absent from the intestinal contents, and trypsin occasionally so.(5) Vagal section appears to be an important factor in the production of the new pattern of response.