Objectives : This study was carried out to investigate the effects of Sasammaickmoondong-tang(SME) on duodenal mucosal lesions induced by indomethacin in mouse. Methods : The normal group is that no inflammation elicitated mouse. Control group is that gastro-inflammation elicitated mouse. Sample group is that SME administered mouseice after gastro-inflammation elicitation. Results : In the common morphology and histochemical change, control group was observed various injury-mucous surface cell, micro-villi, paneth cell, surface epithelial cell, goblet cell-by hemorrhagic erosion, while sample group was as same as normal group. In the immunohistochemical change, the distributions of COX-1, Bcl-2, and BrdU treated with SME noticeably increased than control group(p<0.05). The distributions of TUNEL, $NF-{kappa}B$, COX-2, $IL-2R-{alpha}$, NK-1.1, ICAM-1, and CD11b/18 treated with SME noticeably decreased than control group(p<0.05). And the distribution of SBA was as same as normal group. Conclusion : According to the above results, it is supposed that Sasammaickmoondong-tang is applicable to duodenal mucosal lesions.