BACKGROUND It is extensively supposed that vegetarian diet could affect cancer progress and increase the influence of formal chemotherapy. OBJECTIVES The present study was designed to determine the effect of the ethanol Bane skin extract against chemo resistant prostate cancer PC3 cells. MATERIALS AND METHODS PC3 and L929 cells were cultivated and then incubated in the ethanol Bane skin extract with various concentrations of 0.78, 1.5, 3.13, 6.25, 12.5 mg/mL in 3 times 24, 48, 72 hours. Cytotoxic effect of the ethanol Bane skin extract on PC3 and L929 cells was examined by MTT assay after 24, 48, and 72 hours. Morphology of PC3 cells was evaluated by Gimsa staining. RESULTS The ethanol Bane skin extract inhibited proliferation and caused cell death with IC50 values of 2.8 mg/mL on PC3 cells and the IC50 was 6.1 mg/mL on l929 cells. Morphological changes and apoptotic bodies were observed in PC3 cells faced with the ethanol Bane skin extract by staining with Gimsa. CONCLUSIONS The ethanol Bane skin extract could repress the growth of PC3 cell line. This inhibitory effect of the Bane extract depended on the dose and the time on PC3. The result of this study shows that the ethanol Bane skin extract includes photochemical and inhibitory function against proliferation and inducer of apoptosis in human prostate cancer PC3 cells and also has less cytotoxic effect on l929 than PC3 cells. The ethanol Bane skin extract might be a good candidate for the new herbal anticancer drug.