OBJECTIVE To investigate the antiproliferative activity of Salvia miltiorrhiza Bunge. (SM) on the castration-resistant prostate cancer (CRPC) cell line DU-145, in vitro and in vivo. METHODS Prostate cancer cell line (DU-145) and normal prostate cell line (RWPE-1) were treated with SM at different concentrations (3.125, 12.5, 25 and 50 μg/mL) to investigate the antiproliferative effects. DNA laddering analysis was performed to investigate the apoptosis of DU-145 cells. Molecular mechanism was investigated by Western blot analysis of p53, Bcl-2, prostate specific antigen (PSA), and androgen receptor (AR). Six-week-old male BALB/c nude mice were randomly divided into normal control group (n=101) and treated group (n=101) which administered 500 mg/kg SM for 2 weeks. Tumor volumes were measured. RESULTS Treatment with SM resulted in a dose-dependent decrease in cell number of DU-145 cells in comparison with RWPE-1. DNA laddering analysis indicated the apoptosis of DU-145 cells. Treatment with SM increased the expression of p53 and reduced the expression of Bcl-2 proteins. The levels of PSA were considerably reduced in SM-treated group compared to the controls, and a decrease in AR expression was observed when cells were treated with SM in the same pattern as a reduction in PSA. In the tumour xenograft study, SM given once a day for 2 weeks significantly inhibited tumour growth. CONCLUSIONS SM might contribute to the anticancer actions such as induction of apoptosis and inhibition of proliferation of prostate cancer cells.