Objective : Moutan Cortex (the root bark of Paeonia suffruticosa Andr.) is widely used in oriental medicine as a remedy for inflammation. However, as yet there is no clear explanation of how MC(Moutan Cortex) affects the production of inflammatory cytokine. This study was to determine the effects of Essence extracted MC on the mast cell-mediated inflammatory responses. Method : We observed the effect of MC on compound 48/80-induced histamine release of rat peritoneal mast cells and the effect of administering MC on PCA in rat. We measured the amount of inflammatory cytokine production induced by the phorbol myristate acetate (PMA) plus calcium ionophore(A23187) in the human mast cell line (HMC-1) incubated with various concentrations of MC. The TNF-$alpha$ protein levels were analysised by Western blot. The TNF-$alpha$, IL-6 and IL-8 secreted protein levels were measured by the ELISA assay. The TNF-$alpha$, IL-6 and IL-8 mRNA levels were measured by the RT-PCR analysis. NF-$kappa$B, phospho-I$kappa$B and MAPKs were exmined by Western blot analysis. The NF-$kappa$B promoter activity was examined by luciferase assay. Result : 1. Enzyme immunoassay indicated that MC suppressed histamine secretion of rat peritoneal mast cells. 2. In PCA dependent on IgE, MC had anti-allergic effect of the internal surface of rat skin. 3. Western blot indicated that MC decreased TNF-$alpha$ protein levels. 4. ELISA indicated that MC decreased TNF-$alpha$, IL-6 but MC had no significant effect on IL-8 in HMC-1 cells. 5. RT-PCR indicated that MC decreased TNF-$alpha$, IL-8 but MC had no significant effect on IL-6 in HMC-l cells. 6. Western blot indicated that MC suppressed the induction of MAPKs, NF-$kappa$B & phospho-I$kappa$B activity in HMC-1 cells. 7. Luciferase assay indicated that MC suppressed the PMA plus A23187-induced NF-$kappa$B promoting activityin HMC-1 cells. Conclusion : In this study, we have found that MC is an inhibitor of NF-$kappa$B, MAPKs & cytokines on the mast cell-mediated inflammatory responses.