The effect of intravenous glucose on pentagastrin-induced submaximal gastric acid secretion was invesgated in 8 patients with uncomplicated duodenal ulcer and normal glucose tolerance. 50 ml of a 50% glucose solution, injected over approximately 3 minutes, was completely without effect on volume, acidity, and acid output. These findings seem to rule out the possibility that the marked inhibition earlier demonstrated after intrajejunal glucose is caused by hyperglycemia.