Abstract: Objective To investigate tumor suppression effect and its mechanism of brown ginseng extraction in H₂₀ tumor-bearing mice.Methods Sixty healthy male Kunming mice were randomly divided into 5 groups:saline group,cyclophosphamide group,low-,medium-,and high-dose brown ginseng treatment groups.Twenty-four hours after the establishment of H₂₀ tumor model,the mice of treatment groups were gavaged with brown ginseng extraction of different doses one time a day consecutively for 9 days.At the end of the treatment,the weight of body,tumor,spleen,and thymus gland,the count of white blood cell(WBC),the content of tumor necrosis factor-α(TNF-α),interleukin-2(IL-2),and interferon-γ(IFN-γ),the activity of superoxide dismutase(SOD),catalase(CAT),and glutathione peroxidase(GSH-Px)were determined for all the mice.Results Compared with that of the saline group,the tumor weight(1.37±0.42 g)decreased significantly,with a tumor inhibitory rate of 39.38% in the high-dose brown ginseng group(P<0.05).Meanwhile,significant increases in spleen index,WBC count,content of TNF-α(100.73±10.25 ng/L),IL-2(62.85±9.92 ng/L),and IFN-γ(209.20±21.59 ng/L),activity of SOD (304.43±39.51 U/mL),CAT(116.24±12.77 U/mL),and GSH-Px(392.46±40.71 U/mL)were observed in the mice of high-dose brown ginseng group.Conclusion Brown ginseng extraction has inhibitory effect on H₂₀ tumor cells in mice and the effect may be related to the extraction-induced increases in immune function and antioxidation capacity of the mice.