Objective To study the reversal effects of artesunate on the multidrug-resistant cell line K562/A02.Methods (1)K562/A02 and sensitive K562 cells were treated with artesunate at different conditions,IC_{50} values of the drug was analyzed by MTT at 48 h;(2) The expression of P-gp concentration in K562/A02 cells after 48 h treated with 100 μg·ml^{-1} artesunate was detected by flow cytometry;(3) The glutathione concentration was examined by biochemical analyses.Results(1) Without adriamycin,the IC_{50} of artesunate on K562 was 13.8 μg·ml^1,that on K562/A02 was 13.62 μg·ml^{-1};with adriamycin,the IC_{50} of artesunate on K562/A02 was 2.64 μg·ml^{-1}.(2) K562/A02 cells displayed high levels of P-glycoprotein compared to their parental K562 cells,artesunate 100 μg·ml^{-1} had no effect on the levels of P-gp expression in K562/A02 cells(P>0.05);(3) Cellular GSH concentration in K562/A02 cells treated with artesunate 100 μg·ml^{-1} for 48 h [(65.040±10.674)mg·(mg pro)^{-1}] was lower than that in K562/A02 cell line[(143.210±25.344)mg·(mg pro)^{-1}] without drugs(P< 0.05).Conclusion Not only does artesunate has the cytotoxicity on K562 and K562/A02,but can also reverse the multidrug resistance of K562/A02.The mechanism is that artesunate interferes with the function of glutathione-glutathione s-transferases,not the expression of P-gp.