Objective To study the reversal effect of adriamycin (ADM) resistance in human breast cancer cell line MCF-7/ADM by realgar (REA) combined with ?-elemene (?-ELE), two types of anticancer drugs. Methods The sensitivity to ADM of MCF-7/ADM cells was studied by MTT assay.The intracellular accumulation of ADM in MCF-7/ADM cells was observed by fluorescent-spectrophotometry. Expressions of P-GP protein and Bcl-2 protein were detected by flow cytometry. Results The combined treatment of REA and ?-ELE could significantly enhance the cytotoxic effect of ADM on MCF-7/ADM cells to 4.2 fold as compared with the treatment of REA or ?-ELE respectively (P