This study was designed to determine the gastroprotective properties of quercetin in ischemia/reperfusion-induced gastric mucosal injury and the involvement of endogenous prostaglandins in this process. Oral pretreatment of rats with quercetin (100 mg.kg-1) 30 min before surgery significantly decreased the length of gastric mucosal lesions. However, lower doses of quercetin (25 and 50 mg.kg-1) only slightly decreased the gastric mucosal injury. Intraperitoneal application of indomethacin (5 mg.kg-1) had no effect in control (sham-operated) animals, but significantly worsened gastric injury in non-treated animals after ischemia/reperfusion. Furthermore, indomethacin only slightly reversed protective effect of quercetin. Non-treated animals showed a marked decrease in adherent mucus after ischemia/reperfusion. On the other hand, application of quercetin prevented this significant decrease even in animals pretreated with indomethacin. It can be concluded that antioxidant properties of quercetin and its mucus protective effect might be the main factors responsible for its protective effect against ischemia/reperfusion-induced gastric mucosal injury., J. Mojžiš, K. Hviščová, D. Germanová, D. Bukovičová, L. Mirossay., and Obsahuje bibliografii