Since ablation of afferent nerves prior to stress results in increased severity of acute gastric mucosal lesions, afferent nerves are thought to mediate protective mechanisms in the stomach. These mechanisms are known to include vasodilation of gastric mucosal vessels; vasodilation is thought to allow the gastric mucosa to respond to injurious substances. However, it is not known whether other aspects of mucosal health, independent of those caused by increased blood blow, are affected by afferent blockade. This study compared gastric blood flow and acute gastric mucosal lesions during stress in rats with either chemical sympathectomy or afferent blockade. The purpose of the study was to compare the lesion index and blood flow in each treatment group. The lesion index was highest in rats with afferent blockade and lowest after sympathectomy. Gastric blood flow was partially preserved after sympathectomy, but was not greatly increased, suggesting that some of the effects observed after afferent blockade are unrelated to changes in blood flow.