Fifty-eight subjects including controls, patients with duodenal ulcer, non-operated or treated with a superselective vagotomy underwent endoscopic fundic and antral biopsies. Histologic classification of the two mucosae was performed. We examined the relationship between the histologic grade of gastritis in the two mucosae, then between the histologic aspect of the antral mucosa and antral gastrin-and somatostatin-cell densities, the basal intraluminal secretion of gastrin and somatostatin. There was a significant correlation between the histologic aspect of fundic or antral mucosa and the age of patients, except in the case of vagotomized patients. Fundic and antral histologic patterns were also correlated in each patient, except for vagotomized. Gastrin and somatostatin cell densities showed no variation in function of the degree of inflammation of non atrophic gastritis. These cell densities showed a tendency to decrease in atrophic gastritis, especially when intestinal metaplasia was present. Intraluminal gastrin secretion was increased in patients with mild atrophic gastritis (p less than 0.05 to p less than 0.02) in comparison with those whose histology was roughly normal. It was also increased in severe atrophic gastritis. The highest intraluminal secretion of somatostatin was observed in patients with mild atrophic gastritis while this secretion fell noticeably in those showing severe atrophic gastritis, as compared to the other groups. This work seems to suggest a relationship between intraluminal peptides and the evolution of gastritis. While results are still preliminary, they do not indicate that these peptides, thus released, play any pathophysiologic role.