Abstract: Objective To investigate the protective effects and the mechanism of artesunate(AR)on injury of RAW264.7 cells induced by endotoxin.Methods A macrophage cell line RAW264.7 was employed in an in vitro experiment.After RAW 264.7 cells were cultured and turned to fusion manner,LP5 and different concentration of AR(2.5,5,10,20μg/ml)were added respectively and co-incubated for 24 hours at 37℃ with 5% CO₂,and to establish blank control group.RT-PCR were used to observe nuclear fatorκB(NF-κB)mRNA expression.The content of inflammatory mediators NO in the conditioned media was tested by nitrate reductase.Results After being stimulated to μlg/ml LPS,NF-κB expression and the content of NO were higher than those in the control group on macrophage signal transduction pathway(P<0.05).AR could significantly down-regulate the increased NF-κB expressions and the content of NO concentration2dependently,as well statistical significance showed compare with LPS group(P<0.05).Conclusion One of the most important anti2damnification mechanism that artesunate could significantly decrease the quantity of NO by downing regulation the expression of NF-κB is the essential factor of LPS signal transduction pathway under LPS.