In this study, the antiulcer activity of lacidipine was investigated on indomethacin-induced gastric ulcer model and it was examined whether the antiulcer effect of lacidipine was related to oxidant/antioxidant parameters in rats. Anti-ulcerative effects of lacidipine were investigated on an indomethacin-induced gastric ulcer model in rats. The antiulcer capability of lacidipine was compared to 20 mg kg-1 famotidine. Results showed that lacidipine prevented the formation of indomethacin-induced ulcers at 2 and 4 mg kg-1 doses significantly. Enzymatic and non-enzymatic antioxidant parameters, such as total glutathione, superoxide dismutase and glutathione peroxidase, were found low and enzymatic and non-enzymatic oxidant parameters, such as myeloperoxidase and malondialdehyde, were found high in the gastric tissues of indomethacin-given rats. Indomethacin acts through not only the inhibition of the synthesis of cytoprotective prostaglandins but also by affecting enzymatic and non-enzymatic, oxidant and anti-oxidant mechanisms.