The influence of fundal gastritis on the location, healing, and recurrence of gastric ulcers was studied by the endoscopic Congo red test. Results indicated a close correlation between the location of ulcers and the extent of fundal gastritis. In general, ulcers were more proximal when fundal gastritis was more severe. Of the ulcers examined, 62.5% of those not associated with fundal gastritis failed to heal, whereas 85.7% of those associated with severe fundal gastritis healed within 3 months. The presence of severe fundal gastritis was associated with a high rate of recurrence of gastric ulcers.