Purpose: Myeloperoxidase(MPO) has been found to be the mediator in various inflammatory diseases. Bacterial infection of the intestine and hypoxia can both lead to inflammatory responses, but the effects of MPO in these phenomena are still unclear. Methods: By building the MPO-/- mice ，we examined relevant inflammatory factors and tissue damage in mice with intestinal Citrobacter rodentium infection and hypoxia. The body weight and excreted microorganisms were monitored. Intestinal tissues were collected 7 days after bacterial infection under hypoxia to undergo HE staining and assess the degree of pathological damage. The levels of TNF-α, IFN-γ, IL-6 and IL-1β inflammatory factors in the serum were quantified using ELISA. PCR, WB and IF assays to determine the expression of chemokines MCP1, MIP2 and KC in the colon and spleen. . Results: Citrobacter rodentium infection and hypoxia caused weight loss , intestinal colitis and splenic inflammatory cells active proliferation in wild type mice and this phenomena was alleviative in MPO-/- mice. Also，the capability of clearing bacteria in MPO-/- mice significantly declined. The level of TNF-α in the serum and spleen was both lower in MPO-/- hypoxia C. rodentium-infected mice than that in wild type mice. The chemokines expression levels of MIP2, KC and MCP1 in the spleen and colon of each bacterial infected group were significantly increased (P<0.05), while in hypoxia, the factors in the spleen and colon were decreased (P<0.05). Meanwhile, The levels of these chemokines in the MPO-/- mice were found to be lower than those observed in the wild type mice. Conclusion: MPO plays an important role of the inflammatory responses in infectious enteritis and hypoxia in mice. Loss of MPO may greatly reduces the body’s inflammatory responses to fight deseases.