In the present study, human mast cell line (HMC-1) and peripheral blood mononuclear cells (PBMNC) were pre-incubated with various concentrations of Fructus xanthii extract solution followed by being stimulated with phorbol myristate acetate and further incubated for 24 hours. The cytokines, in cell culture supernatants, of interleukin (IL)-4, IL-6, IL-8, GM-CSF, and TNF-alpha in the supernatant were measured by enzyme-linked immunosorbent assay. The results demonstrated that Fructus xanthii could modulate the mast cell-mediated and PBMNC-mediated inflammatory and immunological reactions modulated by cytokines. And our study supplied the evidence of the mechanisms of Fructus Xanthii in treating inflammatory and allergic diseases.