O. diffusa, C. appendiculata and F. thunbergii are reported to possess many pharmacological activities including anti-oxidant, anti-inflammatory, anti-hypertension, anti-diabetic and anti-cancer effects. However, their anti-cancer activities in human breast cancer have not been clearly elucidated yet. Objectives: In the present study, we compared the in vitro cytotoxic effects of single and complex treatment of O. diffusa, C. appendiculata and F. thunbergii in human breast cancer MDA-MB-231 cells. Methods: After we treated human breast cancer MDA-MB-231 cells with O. diffusa, C. appendiculata and F. thunbergii. we evaluated viability, growth inhibition, morphological changes, apoptotic body formation, measurement of the cell cycle and formation of DNA fragmentation of these cells. Results: We found that single treatment of O. diffusa and F. thunbergii could inhibit cell proliferation in human breast cancer MDA-MB-231 cells. However, complex treatment of O. diffusa, C. appendiculata and F. thunbergii had weak or no effect on the cell proliferation of MDA-MB-231 cells. The first, anti-proliferative effects of O. diffusa in MDA-MB-231 cells was associated with G2/M arrest of cell cycle and apoptotic cell death. The second, anti-proliferative effect of F. thunbergii in MDA-MB-231 cells was associated with apoptotic cell death. Conclusions: Taken together, these findings suggest that O. diffusa and F. thunbergii may be a potential chemotherapeutic agent for the control of human breast cancer cells, further studies will be needed to identify the molecular mechanisms.