Abstract: The use of eriocalyxin B in the manufacture of medicaments for treating leukemia, wherein the leukemia include leukemia containing AML1-ETO fusion protein, acute promyelocytic leukemia, acute myelocytic leukemia and lymphocytic leukemia. Eriocalyxin B increases the level of peroxidate and influences the phosphorylation and degradation of I?B? to prevent NF-?B from getting into the nucleus in order to inhibition NF-?B pathway. Eriocalyxin B can decrease the phosphorylation of ERI1/2 and inhibit MAPK pathway. Eriocalyxin B can extend the life span of mice and decrease tumor volume in mice model of C57 leukemia and tumor transplantation.