Objective: To study the anti-tumor effects of the ferment liquid (FL) and to explore the anti-mutagenic effects induced by cyclophosphamide (CP). Methods: Anti-tumor effects and Anti-mutagenic effects induced by cyclophosphamide (CP) of the ferment liquid were observed in tumor-bearing mice in vivo. Spleen lymphocytes proliferation of mice was stimulated by ConA and NK cell activity was analyzed by the lactate dehydrogenase (LDH) release assay. Results: FL Ⅰ ,FL Ⅱ and FL Ⅲ of 16.7, 33.3 and 66.6ml/kg inhibited growth of Sarcoma 180 sighificanth by 11.6%, 24.2%, 28.0%, 4.8%, 15.2%, 2.2% and 2.1%, 8.5%, 5.2%respectively. Polychromatic erythrocytes (PCE) at all doses of FL Ⅰ and FL Ⅱ were greatly decreased compared with control group ( P ＜0.05), but FL Ⅲ has no inhibition effents( P ＞ 0.05). Production of IL-2 showed no significant difference between all treatment groups.The NK cell killing activity in all treated mice increased by FL Ⅰ and FL Ⅱ was significantly potentiated compared to controls ( P ＜0.05). Lymphocytes proliferation of ICR mice were stimulated by ConA 2.5 ml/L and there were no differences between groups.Conclusion: The present data suggested that three kinds of ferment liquid used as health drink have anti-mutagenesis, immune enhancement effects and showed certain inhibitory effects on S180 tumor growth in vivo.