Objective To investigate the inhibitory effects of hydrogen-rich water ([H]H₂O) against tumor growth in mice with colorectal cancer and the related molecular mechanisms. Methods Mice were vaccinated with SW480 cells suspension (4×10⁶ cells/mice) to establish mouse model of colon cancer. The mice in[H]H₂O intervention group were freely allowed to drink[H]H₂O (0.8 mg/kg), which was refreshed three times daily, and the mice in control group were given light water. The tumor weight and volume were measured 28 d after bearing tumor to assess tumor growth, the expression of Ki-67 protein was examined by immunohistochemical method, the apoptosis of tumor cells was observed by TUNEL, and the levels of oxidized glutathione (GSSG) and glutathione (GSH) were analyzed using colorimetric method. Micro array was used to screen the differentially expressed genes between control group and[H]H₂O intervention group, and the levels of those genes were verified with qRT-PCR. Results Compared with the control group,[H]H₂O intervention significantly inhibited the tumor growth, reduced tumor weight and volume (P<0.01, P<0.05); moreover, it also reduced the expression of Ki-67 protein (P<0.05) and promoted tumor cell apoptosis (P<0.05). In addition, the ratio of GSSG/GSH was significantly increased in[H]H₂O intervention group compared with that in the control group (P<0.05).[H]H₂O intervention could also regulate the expression of interferon γ-related genes. Conclusion [H]H₂O may exert its antitumor activity via inhibiting proliferation, inducing apoptosis of colon cancer cells, and regulating the intracellular redox state and the expression of interferon γ-related genes.