Glutamine, a major fuel for enterocytes, stimulates water and sodium absorption in animal models of secretory diarrhea, but data in humans are still limited. The aim of this study was to investigate the effect of glutamine on jejunal absorption during hypersecretion in humans. In six healthy adults, the effects of glutamine on jejunal absorption were assessed with a triple lumen tube on two occasions at baseline and during PGE₁-induced hypersecretion (0.1 µg. kg^-1. min^-1), in a random order. Isoosmolar solutions containing PEG 4000 as non-absorbable marker were infused in the jejunum at 10 ml x min^-1 over one-hour periods: saline (sodium chloride 308 mmol/L), glucose:mannitol 45:45 mM, glucose 90 mM, alanine:glucose 45:45 mM, glutamine:glucose 45:45 mM, glutamine 90 mM. Net absorptive and secretory fluxes were measured at steady-state. At baseline, glutamine and alanine-containing solutions induced a three-fold increase of water and sodium absorption (p<0.05); 90 mM glutamine stimulated water absorption more than 90 mM glucose (3.6 ± 0.6 vs 1.9 ± 0.3 ml x min^-1 x 30 cm^-1, p<0.05). PGE₁-induced hypersecretion was reduced (p<0.05) by solutions alanine:glucose, glutamine:glucose and glutamine 90 mM (p<0.05), and reversed to absorption by alanine:glucose and glutamine:glucose. Glutamine and alanine absorption was nearly complete, and not influenced by PGE₁. In conclusion, glutamine stimulates water and electrolyte absorption in human jejunum, even during experimental hypersecretion. In addition to the metabolic effects of glutamine, these results support the evaluation of glutamine-containing solutions for the rehydration and the nutritional support of patients with secretory diarrhea.