Purpose: It is the purpose of this study to investigate the anti-inflammatory effects of water extract from Gagamsoyosan(GGSYS) on the peritoneal macrophage. Methods: To evaluate anti-inflammatory effects of GGSYS. inflammatory cytokines were measured in lipopolysaccharide(LPS) -stimulated macrophages. Furthermore. the western blot has been done to look into the molecular mechanism. Results: GGSYS did not have any cytotoxicity in the peritoneal macrophages and suppressed production of LPS-induced NO. tumor necrosis factor-alpha (TNF-$alpha$). interleukin(IL)-1$eta$. IL-6. IL-12. GGSYS inhibited the activation of extracelluar signal-regulated kinase (ERK1/2). c-Jun N-terminal kinase(JNK), p38 kinase and the degradation of inhibitory kappa B-alpha($I_{k}B-alpha$) in the LPS-stimulated peritoneal macro phages. GGSYS inhibited LPS-induced endotoxin shock and the production of TNF-$alpha$. IL-l$eta$. IL-6 in serum from LPS-stimulated mice. Conclusion: These results suggest that GGSYS may have the anti-inflammatory effect which can inhibit the production of NO and inflammatory cytokines. GGSYS is expected to protect against inflammatory diseases.