Objectives : This study was carried out to investigate the effects of sihogeji-tang on indomethacin-induced gastric mucosal lesions in rats. Methods : Experimental rats were classified into three groups. The normal group had no inflammation elicited. The control group was rats administered water after elicitation of gastro-inflammation. The sample group were administered sihogeji-tang after gastro-inflammation elicitation. Results : In the common morphology and histochemical change, the control group were observed to have various injuries by hemorrhagic erosion, while the sample group had noticeably fewer injuries than the control. In the immunohistochemical change, the distribution of HSP-70, PCNA treated with sihogeji-tang noticeably increased over the control group. The distribution of NF-kB, COX-2 treated with sihogeji-tang noticeably decreased compared to the control group. (p<0.05) Conclusions : Sihogeji-tang had significant effects on indomethacin-induced gastric mucosal lesions in rats.