To investigate the cell proliferation inhibition and apoptosis induced by berberine a-hydroxy f-decanoylethyl sulfonate (HB) on MDA-MB-231 cells in vitro, and the inhibitory effect of HB on the expression of poly adenosine diphosphate RNA polymerase (PARP), MTT assay was used to detect the viability of MDA-MB-231 cells and cell cycle was examined by flow cytometry. The results showed that HB could significantly inhibit the proliferation of MDA-MB-231 cells, and mildly arrested cell cycle progression at S phase. The IC50S for 24, 48 and 72 h treatment were 4.65, 1.46 and 0.75 mg.L-1 (7.55, 2.37 and 1.22 micromol.L-1), respectively. Annexin V-FITC/PI double staining assay showed that HB increased apoptotic ratio of MDA-MB-231 cells. Western blotting analysis showed the expressions of procaspase-3, procaspase-9 and PARP were decreased after HB treatment, while their fragment increased. The results suggest that HB can inhibit the growth and induce apoptosis of MDA-MB-231 cells, which may be associated with inhibition of the expression of procaspase-3, procaspase-9 and PARP.