White blood cells are the defense guards of the organism, when the organism is invaded by external substances, such as bacterial viral infections, white blood cells will proliferate, which can play a role in destroying bacterial viruses. Normal human body white blood cells are within a certain range, if the white blood cells are too low, it will cause the body’s immunity to decline, easy to combine with bacterial and viral infections, including fungal infections, resulting in a lack of body resistance. Clinically, there are many common causes of low white blood cells, the most common is the blood system diseases, such as leukemia, aplastic anemia, rheumatic immune system diseases, such as systemic lupus erythematosus or the role of certain drugs, including special viral infections, can cause the body to reduce white blood cells. Therefore, it is important to find out what caused the decrease in white blood cells. If too low clinically will need to use some drugs, such as shark liver alcohol, b4 oral elevation of white blood cells or some colony-stimulating factor to elevate white blood cells, so as to enhance the resistance, otherwise the patient is very easy to combine with bacterial infection. At the same time to find out what causes the white blood cell lowering, if it is the drug factor can stop the drug, the white blood cell will be restored. If it is a rheumatic immune system disease, it can be treated with immunosuppressants or hormones. If it is a blood disease, active treatment for the blood disease is necessary to make the white blood cells recover completely.