If the white blood cells are elevated after chemotherapy for breast cancer, it is necessary to go to the hospital in time to clarify the cause of the disease and receive appropriate treatment under the guidance of the doctor. If the white blood cells are found to be elevated after chemotherapy, one may be caused by the use of white blood-boosting drugs, and the other may be caused by infectious diseases. We need to choose the treatment according to the condition, and after excluding the possibility of infection, dynamic observation is enough and no special treatment is needed. During chemotherapy, patients may damage the bone marrow function, and chemotherapy often causes white blood cells to drop, resulting in patients’ resistance and immunity to be lowered. If the white blood cells increase after chemotherapy for breast cancer, the cause of the disease should be clarified and appropriate treatment should be accepted under the guidance of doctors.