Objective Tripterygium wilfordii Hook. f. has been used for centuries in traditional Chinese medicine to treat autoimmune disease associated with increased production of the pro-inflammatory cytokine. Triptolide( TP) is a compound originally purified from T. wilfordii Hook f. and it has potent anti- inflammatory and immunosuppressant activities. In this study, we investigated the effect of TP on secretion of NO and IL-6 in celiac macrophages ( MΦ) activated by lipopolysaccharide ( LPS) in Kunming mice. Methods Celiac MΦ of mice were separated, purified, and activated by LPS, then cultured in vitro with TP of different concentrations. The level of NO in cellular supematants was determined by Griess reagent, and that of IL-6 was determined by ELISA. Results We found that pro-inflammatory cytokine NO activity in MΦ induced by LPS was significantly inhibited by TP ( 10-3-10 μg/ml) from 4-24 h in a time and dose- dependent manner (P < 0. 01). The level of IL-6 in MΦ was significantly inhibited by TP (10-3-10 μg/ml) at 12 h in a dose-dependent manner (P <0. 01). Conclusions We demonstrated that TP can inhibit levels of NO and IL-6 in celiac MΦ of Kunming mice activated by LPS.