Abstract: Objective To observe the protection of E838 on cyclophosphamide -induced mice's injury. Methods The E838 were injected into mice intra peritoneally for 5 days, and the positive control group was madder diester. CTX was injected on the third day. We observed the changes in peripheral blood leukocytes, bone marrow nucleated cells, endogenous spleen nodule formation (CFU-S), spleen and thymus index. Results E838 can significantly reduce the chemotherapy-induced immune function inhibition in mice,and accelerate the weight grow after chemotherapy.Numbers of peripheral blood leukocytes bone, marrow nucleated cells and CFU-S significantly increased compared with the control group and there was significant statistically difference (P<0.05). There was significant statistically difference (P<0.05)in the numbers of blood leukocytes of middle and high dose group compared with madder diacrylate. Conclusion E838 can antagonize the chemotherapy injury.