AIM: Nonsteroidal anti-inflammatory drugs (NSAIDs) cause gastrointestinal damage as one of their side effects in humans and experimental animals. Lipid peroxidation plays an important role in NSAID-induced ulceration. The aim of this study was to investigate the inhibitory effect of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors on the ulceration in small intestines of rats. METHODS: The effects of three HMG-CoA reductase inhibitors, fluvastatin, pravastatin and atorvastatin on ileal ulcer formation in 5-bromo-2-(4-fluorophenyl)-3-(4-methylsulfonylphenyl) thiophene (BFMeT)-treated rats were examined. Antioxidative activity of the inhibitors was measured by a redox-linked colorimetric method. RESULTS: Fluvastatin, which was reported to have antioxidative activity, repressed the ileal ulcer formation in rats treated with BFMeT an NSAIDs. However, the other HMG-CoA reductase inhibitors (pravastatin and atorvastatin) did not repress the ileal ulcer formation. Among these HMG-CoA reductase inhibitors, fluvastatin showed a significantly stronger reducing power than the others (pravastatin, atorvastatin), CONCLUSION: Fluvastatin having the antioxidaitive activity suppresses ulcer formation in rats induced by NSAIDs. AIM: Nonsteroidal anti-inflammatory drugs (NSAIDs) cause gastrointestinal damage as one of their side effects in humans and experimental animals. Lipid peroxidation plays an important role in NSAID-induced ulceration. The aim of this study was to investigate the inhibitory effect of 3 METHODS: The effects of three HMG-CoA reductase inhibitors, fluvastatin, pravastatin and atorvastatin on ileal ulcer formation in 5-bromo-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors on the ulceration in small intestines of rats. Antioxidative activity of the inhibitors was was measured by a redox-linked colorimetric method. RESULTS: Fluvastatin, which was reported to have antioxidative (2-fluorophenyl) -3- (4-methylsulfonylphenyl) thiophene activity, repressed the ileal ulcer formation in rats treated with BFMeT an NSAIDs. However, the other HMG-CoA reductase inhibitors (pravastatin and atorvastatin) did not repress the ileal ulcer formation. Among th ese HMG-CoA reductase inhibitors, fluvastatin showed a significant reducing power than the others (pravastatin, atorvastatin), CONCLUSION: Fluvastatin having the antioxidaitive activity suppresses ulcer formation in rats induced by NSAIDs.