A compound (Zhu-xiang) from herbal extracts containing ginseng and carthamus tinctorius was used to treat the MDA-MB-231 breast cancer cell and normal human mammary gland cell lines. The inhibition of cell proliferation by Zhu-xiang, epirubicin, 5-fluorouracil and cyclophosphamide was determined by WST-1 assays. The apoptotic effect was studied by flow cytometry analysis of DNA strand breaks and ApopTag Peroxidase In Situ Apoptosis kit by the TUNEL assay. The proliferation index as well as cell cycle progression were also evaluated by flow cytometry using Ki-67 and propidium iodide respectively as markers. The Zhu-xiang showed significantly inhibition in cell proliferation and the inhibition was dose dependent. The inhibitory effect of Zhu-xiang was significantly greater than commonly used cytotoxic drugs. The inhibitory effect is a result of the induction of apoptosis, which is concentration- and time-dependent. DNA histograms indicate that the compound causes accumulation of cells mainly in the S phase. The viability of cells in breast solid tumours was measured by ATP bioluminescence assay to determine the drug-induced cytotoxicity of Zhu-xiang. The three different concentrations of Zhu-xiang all exhibited the ability to inhibit proliferation in solid tumour. Zhu-xiang could be a useful anti-cancer compound against breast cancer.