ObjectiveTo observe the anticancer efficacy of ginsenoside Rg3 on colorectal cancer in vitro and in vivo. MethodsMice colorectal cell line (CT26) was incubated in 96-well plates (3×103-4×103 per well) with various concentrations of ginsenoside Rg3 (0, 5, 10, 15, 20 μg/mL) for 24 hours and 48 hours. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-dipheny 1-2-H-tetrazolium bromide assay was used to detect the inhibitory rate of cells. Xenograft models were established by subcutaneous implantation of CT26 cells into BABL/c mice. Each mouse was injected with 1×107 cells suspended in serum-free medium. Xenograft mice were randomized into four groups: physiological saline group, ginsenoside Rg3 5 mg/kg group, ginsenoside Rg3 10 mg/kg group, and ginsenoside Rg3 20 mg/kg group. Ginsenoside Rg3 was administrated to mice by intragastric gavage. All animals were observed for activity, body weight, tumor size, survival time, mental state and adverse effect of ginsenoside Rg3. Hematoxylin-eosin stain was used for comparing necrosis rate among groups. ResultsThe inhibitory rates of cells were increasing following the elevating concentrations of ginsenoside Rg3. The anti-proliferation effect of ginsenoside Rg3 for 48 hours was weaker than the anti-proliferation effect for 24 hours. The decrease of mice body weight was slower than physiological saline group after administration of ginsenoside Rg3, and the number of mice with worse physiological state, lack of activity and loss of appetite in physiological saline group were more than that in ginsenoside Rg3 groups. However, these results among four groups were not significantly different (P>0.05). There were no obvious adverse effects of ginsenoside Rg3 found during the whole study. The necrosis rate of physiological saline group, Rg3 10 mg/kg group and Rg3 20 mg/kg group was 20%, 60% and 80% respectively. ConclusionGinsenoside Rg3, as a single agent, still has anticancer activity. The anticancer efficacy is increasing following the elevating concentrations of ginsenoside Rg3. Ginsenoside Rg3 is a dose dependent agent.