Silibinin is the major active molecule of silymarin, the mixture of flavonolignans extracted from Cirsium japonicum (CJ). It has been used for treatment of hepatitis and inflammation related diseases. The aim of this study was to prove whether Silibinin has effectiveness for allergic inflammation. Silibinin processes the inflammatory reaction in phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187 (PMA plus A23187) stimulated human mast cell line (HMC-1). Its effect was examined by ELISA, RT-PCR, Western blot, and Luciferase assay. The results were Silibinin inhibited the expression of histamine, TNF-$alpha$ (tumor necrosis factor-$alpha$), IL-6 (interleukin-6), and IL-8 (interleukin-8). Silibinin suppressed NF-${kappa}B$ (nuclear factor kappa B) activation in stimulated HMC-1 (human mast cell-1). This effect was mediated through inhibition of phosphorylation and degradation of $IkB{alpha}$, an inhibitor of NF-kB. Silibinin significantly inhibited induction of NF-kB promoter mediated Luciferase assay. These results suggest that Silibinin has a potential molecule for therapy of mast cell-derived allergic inflammatory diseases.