Multidrug resistance(MDR)of tumor cells has become the main impediment that influence the curative effect of cancer chemotherapy. Although there are many mechanisms can generate the multidrug resistance, the overexpression of P-glycoprotein encoded by the multidrug resistance-1(mdr1) gene is the main cause in the formation of MDR. Seaching for innocuous and effective reversal of MDR is not only a method of improving the efficiency of cancer chemotherapy but also the problem desiderated to be resolved in chemotherapy domain.