Gastric mucosal barrier, drug-induced acute erosive gastritis and stress ulcer.

Gastric mucin probably plays an insignificant role in the protection of gastric mucosa. The metabolic integrity of the mucosal cells is important in the maintenance of the gastric mucosal barrier. Various drugs and "stress" break the gastric mucosal barrier, allowing increased back diffusion of hydrogen ions and causing gastric erosions, stress ulcers, and gastric bleeding. Presence of acid seems to be necessary for the occurrence of these lesions. Acute gastric mucosal lesions as a cause of upper gastrointestinal bleeding are best diagnosed by fiberoptic endoscopy. Antacids may be effective in preventing these lesions.