Chemotherapy is the common treatment for advanced breast cancer, but the toxic side effects of chemotherapy are more serious, especially the bone marrow suppression after chemotherapy leads to leukocyte reduction, and in severe cases, high fever and even life-threatening. The normal value of leukocytes is usually at (4.0-10.0) × 109/L, or sometimes 4000~10,000/mm3, and those below this value are considered low leukocytes. Mild leukocytopenia can be treated without treatment and can gradually return to normal after resting for a period of time. Moderate leukocytopenia can be treated with oral leukocyte-raising drugs such as vitamin B4, shark liver alcohol, lisinopril, and white-raising tablets if there are no symptoms of infection. However, if the total white blood cell count is lower than 1.5×109/L or the neutrophils are lower than 0.5×109/L, there is a risk of serious infection or even life-threatening, so hospitalization is needed for observation and treatment with granulocyte colony-stimulating factor.