Normal human blood leukocyte count is 4000～10000/cubic millimeter. Leukocytes in the blood for a long time below 4000 / cubic millimeter, the percentage of neutrophils normal or slightly lower, called leukopenia. The causes of the disease include chemical factors (drugs, benzene and derivatives), bacterial and viral infections, various types of radiation, congenital factors and others such as leukemia and malignant tumors. Most patients with leukopenia feel dizziness, limb weakness, fatigue, loss of appetite, low-grade fever, chills, lumbago, insomnia and dreams, etc. Some of them suffer from recurrent colds, otitis media, pneumonia, bronchitis, and urinary and biliary tract infections. Patients with granulocyte deficiency often have a rapid onset of symptoms, headache, chills, high fever, fatigue, and then secondary infections, necrotizing ulcers can occur in the throat, nasal cavity, skin, rectum, vagina, anus and other places. It is recommended that you go to the hospital for timely examination to rule out the possibility of certain diseases. Due to the decrease of normal white blood cells, it is very easy to be infected by bacteria, viruses and other microorganisms, so the prevention of infection is a very important part of daily life for patients and their relatives. Infection prevention mainly includes the following aspects: (1) Ensure a clean living environment: keep the living room as simple and clean as possible, keep things such as dunnage dry and disinfected every day, don't put flowers and plants indoors, and don't leave static water in the utensils; minimize the number of visitors and isolate people suffering from colds, pneumonia, tuberculosis, hepatitis, etc., in order to prevent contagion. Wear a mask when you go out. Try not to go to the public **** places with large flow. (2) Do a good job of personal hygiene. Keep the skin and mucous membranes clean, underwear should be changed, disinfected, dried in the sun, bathed daily, meticulous personal hygiene. Maintain oral hygiene, prevent oral infection, rinse the mouth frequently, use the mouthwash given by the doctor, gargle every 2 hours or so; clean the mouth at any time when eating; avoid eating stimulating food; prevent dry lips and bleeding infections, can be coated with edible oil or paraffin oil; brush the teeth with soft bristles with gentle movements to prevent bleeding gums and infections; if there are ulcers and vesicles in the oral mucous membranes, can be locally coated with gentian violet or medication according to the doctor's prescription. Keep the perineum and anus clean to prevent urinary tract infection and anal abscess: wash the perineum every day, wash the anus after each bowel movement, wash with warm water, special pots for special use, wash the perineum first, then wash the anus. When there is localized infection, different medicinal solution can be used according to the doctor's requirements, such as potassium permanganate solution. Drink more water, keep the bowel movement, such as constipation timely relief, to prevent defecation difficulties, resulting in anal bleeding infection. Drink more water, but also conducive to flushing the urethra, to prevent urinary tract infections, such as increased frequency of urination at the same time there is urgent and painful urination, indicating that there is a urinary tract infection. If there is pain in defecation, there may be an anal abscess. Both of these situations should be timely to find a doctor. (3) Ensure a clean diet: eat only steamed fruits and vegetables, and steam and sterilize eating utensils daily. (4) Add or subtract clothing appropriately according to the climate to prevent catching cold and flu. (5) Do coughing, deep breathing and other exercises regularly to avoid pneumonia.