In this study, we evaluated the antiproliferative effects of Panax notoginseng, ginsenoside Rb1, and notoginsenoside R1 in the human breast carcinoma MCF-7 cell line. Our results indicated that both Panax notoginseng radix extract (NRE) and Panax notoginseng rhizoma extract (NRhE) possess significant antiproliferative activities in MCF-7 cells. Compared to control group (100%), at the concentrations of 0.05, 0.5, and 1.0 mg/ml NRE, cell growth was concentration-dependently reduced to 81.0 ${pm}$ 6.1 (P < 0.01), 34.2 ${pm}$ 4.8 (P < 0.001), and 19.3 ${pm}$ 1.9 (P < 0.001), respectively. Similar results with NRhE at concentrations of 0.5 and 1.0 mg/ml were obtained in these MCF-7 cells. To identify the responsible chemical constituent, we tested the antiproliferation effects of two representative saponins, ginsenoside Rb1 and notoginsenoside R1, on the MCF-7 cells. The data showed that ginsenoside Rb1 was endowed with antiproliferative properties, while notoginsenoside R1 did not have an inhibitory effect in the concentrations tested. Our studies provided evidence that Panax notoginseng extracts and ginsenoside Rb1 may be beneficial, as adjuvants, in the treatment of human breast carcinoma.