There are three main components in human blood, namely white blood cells, red blood cells and platelets, each performing its own function. One of the functions of leukocytes is to resist invasion by foreign enemies. When bacteria, viruses, parasites and other harmful microorganisms invade the body, leukocytes proliferate, differentiate, mature and destroy these harmful substances; in addition to resisting invasion by foreign enemies, leukocytes are also responsible for destroying aging, dead, diseased and cancerous cells and tissues in the body. Therefore, leukocytes are very important. The normal value of leukocytes in the peripheral blood of a normal adult is 4-10×109/L. Below 4×109/L is leukopenia. Leukopenia can be characterized by weakness of the limbs, fatigue, fatigue, muscle aches, dizziness, susceptibility to illness, colds, fever, decreased body resistance, and in severe cases, serious multi-organ infections of the whistle, digestive tract, etc., manifested as high fever, cough and phlegm, abdominal pain and diarrhea, and even infection poisoning, shock, etc. It can be seen that low white blood cells for the human body are mainly harmful: 1, low white blood cells is caused by the body’s defense mechanism is significantly reduced, vulnerable to external bacteria, viruses, parasites, inducing a variety of diseases on the body hair. This is the reason why the body suffers from disease when the body’s white blood cells are low. 2, low white blood cells is caused by the body’s immune system function is weakened. White blood cells have the role of engulfing and destroying viruses and bacteria that invade the body, so if the white blood cells are low, the chances of the body contracting diseases will increase greatly. 3. Low white blood cells can even cause sepsis in severe cases, with a mortality rate of 30-40%. This is the biggest threat of low white blood cells to human health. For low white blood cells is the need to pay sufficient attention to the cause of treatment, to find the cause of white blood cell reduction, if it is malnutrition, then you need to supplement nutrition. If it is chemotherapy that causes leukopenia, it may be necessary to adjust the dosage of the drug. If it is leukemia, then treatment will need to be initiated for the leukemia. If it is caused by a bad environment, then it is necessary to consider a change of working environment.