Cirsium japonicum var. ussuriense is often used in treatment of human disease such as hemorrhage, blood congestion and inflammation. The present study has been undertaken to investigate the effect of the leaf extract from C. japonicum var. ussuriense (CLE) on the development of collagen-induced arthritis (CIA) in DBA1/J mice. CLE administration suppressed markedly the arthritis incidence and arthritis score in CIA mice. Also, CLE significantly suppressed the release of $PGE_2$, TNF-${alpha}$, IL-4 and IL-6 in CIA mice. However, CLE significantly increased the production of IL-10, but not IL-4. These results suggest that CLE suppress inflammatory mediators and regulates Th1 and Th2 cytokines. These properties may contribute to the anti-arthritis action of CLE.