The spread of capsule endoscopy has led to a focus on small intestinal injury induced by non-steroidal anti-inflammatory drugs (NSAIDs). However, it has been proposed that proton pump inhibitors (PPI), a strong anti-secretary agent, have anti-inflammatory action beyond acid suppression. Therefore, we evaluated the biological effects of lansoprazole, a PPI used in the clinical area, in the setting of experimental rat non-steroidal anti-inflammatory drug-induced enteritis. The animals were given indomethacin subcutaneously and the intestinal mucosa was examined 24 h later. Lansoprazole was given subcutaneously just after following indomethacin injection. Single administration of indomethacin at 10 mg/kg provoked severe hemorrhagic lesions in the small intestine, mostly the jejunum and ileum. The levels of thiobarbituric acid-reactive substances (TBARS), the myeloperoxidase (MPO) activity and the content of cytokine-induced neutrophil chemoattractant-1 (CINC-1) in the intestinal mucosa significantly increased in indomethacin-treated groups compared with the sham-operated groups. The development of intestinal lesions in response to indomethacin was dose-dependently prevented by lansoprazole at a dose of 5 mg/kg together with significant suppression of the increased level of TBARS, MPO activities and CINC-1 in the small bowel. Furthermore, the increased CINC-1 mRNA expression after administration of indomethacin was also inhibited by treatment with lansoprazole. These results suggest that lansoprazole administered exogenously prevented the small intestine against indomethacin-induced damage, the action being dependent on its anti-inflammatory and anti-oxidative responses. This evidence supports the theory that PPI have an expanding role beyond acid suppression.