Experimental reactivation of chronic gastric lesions induced by acetic acid injection to the rat stomach was produced after exposure of the animals to different secondary damaging conditions. On day 18 after the initial injury, animals (n = 100) were distributed in five groups. One of them was used as control and the remainder were subjected to absolute ethanol, stress, pyloric ligation or aspirin. Measurements of gastric acid secretion were performed. Pyloric ligation resulted in the maximal rate of acid secretion. Computerized morphometric analysis of the gastric injuries showed a significant association (70%, p < 0.01) of hemorrhagic lesions with the primary site of chronic injury in animals subjected to pyloric ligation. No significant association was observed after absolute ethanol (30%), aspirin (30%) or stress (35%). The presence of hemorrhage associated with the original gastric lesions was more dependent on the disorganization of the lamina propria and proliferation of chief cells in the margins of the mucosal scar than on the severity or extent of the chronic lesions. These results indicate that local conditions at the level of gastric mucosa together with an increased presence of acid in the gastric lumen provide favorable conditions for the reactivation of primary chronic lesions in the rat.