Elderly multiple myeloma patients, low fever after advanced chemotherapy is mainly due to chemotherapy drugs, infection and other causes. 1. Drug effect: after chemotherapy for multiple myeloma in the elderly, it will lead to the destruction of malignant myeloma cells, which will trigger the human body to produce low fever reaction. There are also some chemotherapy drugs itself can cause fever, such as cyclophosphamide, dexamethasone and so on. 2. Mild or severe infection: the elderly themselves have poor physical condition, coupled with the fact that during the use of chemotherapeutic drugs, the hematopoietic function of the human bone marrow is inhibited, leading to a decrease in the number of white blood cells, thus the immunity decreases, which can easily lead to a series of infections (e.g., pneumonia, etc.), and so the patient will have symptoms of low fever. If the above symptoms occur, it is recommended to go to the hospital in a timely manner, under the guidance of the physician early formal treatment, so as not to delay the condition.