The decrease of white blood cells after chemotherapy often occurs with generalized weakness, fever, body pains and aches. Chemotherapy is an important way to treat malignant tumors, chemotherapy will produce bone marrow suppression, resulting in patients will have a drop in white blood cells, clinical manifestations of general weakness, fever and even body pain and other phenomena. White blood cell decline may cause immunity decline, leading to infection and fever, be careful to identify, these patients need to give anti-infection treatment. Patients need to undergo routine blood tests to assess the number of white blood cells and medication is required if necessary. If the patient has severe pain and fever, fever reduction and pain relief need to be given. In recent years, the probability of leukocyte decline can be reduced by prophylactic use of drugs, which can effectively improve the patient’s adverse reaction situation as well as the quality of life. It is recommended that patients follow the doctor’s instructions to actively cooperate with the treatment.