NSAIDs compromise gastroduodenal defense mechanism mediated by inhibiting cyclooxygenase and leading to leukocyte infiltration or neutrophil adherence, and cause gastric ulcers. There are a number of mucoprotective drugs in Japan, and they were often used for NSAIDs-induced ulcer treatment. In vitro or in vivo studies, some mucoprotective drugs have been shown to have anti-inflammatory action due to the inhibition of leukocyte infiltration, production of inflammatory cytokines. However, mucoprotective drugs were given a low priority in "the Japanese guideline for the management of gastric ulcer" edited in 2003. Therefore, mucoprotective drugs should be investigated in terms of effects on NSAIDs-induced gastric ulcer patients because there are a few reliable evidences for the treatment of NSAID-induced gastric ulcer in Japan.