Objective : Lacca Sinic: Exsiccate (LSE) extracted from Rhus vemicitlus Stokes (RVS) has been used traditionally as a remedy for inflammation in Korea, China, and Japan. However, as yet there is no clear explanation of how LSE affects the production of inflammatory cytokines. This study was to determine the effects of LSE on the mast cell-mediated inflammatory responses. Method : We measured the amount of inflammatory cytokine production induced by the phorbol myristate acetate (PMA) plus calcium ionophore(A231S7) in the human mast cell line (HMC-l) incubated with various concentrations of Laces Sinica Exsiccate (LSE). 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. Nuclear and cytoplasmic proteins were examined by Western blot analysis. The NF-${kappa}B$ promoter activity was examined by a luciferase assay. Result : LSE inhibited the PMA + A231S7-induced $TNF-alpha$, IL-6, and IL-8 expression and suppressed NF-${kappa}B$ activation in the stimulated-HMC-1. In addition, LSE inhibited induction of NF-${kappa}B$ promoter-mediated luciferase activity. Conclusion : In this study, we have found that LSE is an inhibitor of NF-${kappa}B$ and cytokines on the mast cell-mediated inflammatory responses.