This study was peformed to investigate possible mechanisms underlying possible effect of Coicis Semen composition (CSC) on inflammatory diseases using in vivo model of RA in the mice. Results are summarized as follows. In production of inflammatory cytokines, INF-${gamma}$ in the spleen and IL-6 in the serum were decreased by CSC treatment. TNF-${alpha}$ in serum was significantly decreased, IL-4 in the spleen was significantly increased by CSC treatment. In production of rheumatoid factors, IgM and IgG were significantly decreased by CSC treatment. The present data suggest that CSC treatment can improve pathological damage by CIA. So we expect that CSC should be used as a effective drugs for not only rheumatoid arthritis but also another autoimmune disease. Therefore we have to survey continuously in looking for the effective substance and mechanism in the future.