White blood cells 40 × 10^9 / L need to pay attention to, early medical treatment, to clarify the cause of the disease. The range of normal value of normal human white blood cells is (4~10)×10^9/L, white blood cells 40×10^9/L is in a more serious indicator, need to clarify the cause of the disease in time and give treatment. Leukocyte 40×10^9/L is more serious, commonly found in acute leukemia, chronic leukemia and so on. Patients should seek early diagnosis, identify the causes of leukocyte increase, such as acute myeloid leukemia to be cytarabine and other drugs chemotherapy, chronic granulocytic leukemia to be imatinib and other drugs. The above drugs should be used under the guidance of a physician.