A drop in white blood cells after the use of chemotherapy drugs is the most common adverse reaction after chemotherapy. Depending on the degree of bone marrow suppression, doctors will give various medications to raise white blood cells. When the white blood cells drop, I should reduce the number of meetings and go out less because the patient’s immunity is lower at this time, and infections can easily occur. Do not contact people with colds to avoid cross infection. If the white blood cells are as low as 1×10^9/L or less, the patient’s room should be sterilized. A common method is to use ultraviolet room disinfection for about 30 minutes twice a day. When irradiating ultraviolet light, the patient has to leave the room, and when they cannot leave the room, they need to cover the exposed skin, such as the face, hands and feet, with a towel or sheet.