Pancreatic and biliary secretion and gastric emptying rates of a liquid test meal (LTM) were determined in normal persons, in patients with subtotal gastrectomy with gastroduodenostomy (STG-BI) or with gastrojejunostomy (STG-BII), and in patients with truncal vagotomy and pyloroplasty (V&P). In all operated persons, rapid gastric emptying diluted intraluminal contents, with consequent abnormally low concentrations of trypsin and bile salts initially, a pattern that was not corrected by addition of intravenous hormones to the meal stimulus. Trypsin output in V&P's after the LTM was significantly depressed to 40% of normal, but was normal in the STG groups. The delay in reaching normal values for trypsin and bile salt concentrations, was more marked in STG-BII owing to sequestration of secretions in the afferent loop. The low luminal concentrations of digestive secretions for the first 60 to 80 min after a LTM are therefore attributable to rapid gastric emptying in all operated groups, and in V&P to a depressed pancreatic enzyme response also. In STG-BII, afferent loop sequestration exaggerates the delay in attainment of normal intraluminal concentrations. The combined disturbance in STG-BII produces greater abnormalities than seen in STG-BI.