AIM: To investigate the reversal effect of neferine on multidrug resistance in human gastric carcinoma cell line. METHODS: Cells of a human gastric cancer cells line, SGC7901, and its vincristine (VCR) -resistant variant, SGC7901/VCR, were cultivated with or without neferine and/or VCR. The cytotoxic effect of VCR was evaluated by the MTT assay. Cell apoptosis induced by VCR was determined by flow cytometry (FCM). The expression of P-glycoprotein (P-gp) and a multidrug-resistance-associated protein (MRP) in cells was examined by immunofluorescence and FCM. RESULTS: Neferine at the concentratio...