Low white blood cells after breast cancer chemotherapy can be injected with long-acting white blood cell boosting injection to enhance the white blood cell count and reduce the risk of infection in patients, and there may be adverse reactions such as skeletal muscle pain, constipation, fatigue, fever, etc., but generally there are no serious side effects. Long-acting leukocyte boosting injection is commonly used polyethylene glycolized recombinant human granulocyte stimulating factor, which can promote the proliferation and differentiation of neutrophils, and the frequency of administration is usually once a week, which can effectively maintain the level of leukocytes of patients undergoing chemotherapy, reduce the risk of post-chemotherapeutic infections, and reduce the number of times of leukocyte boosting injection for the patients. Common adverse reactions to polyethylene glycolized recombinant human granulocyte stimulating factor include skeletal muscle fleshing pain, malaise, fever, diarrhea, constipation, etc. Most of them are relatively mild, and the most common one is bone pain, which can be relieved with the help of acetaminophen and other medications, and these side effects are very common in short-acting leukapheresis injections as well. Once a breast cancer postoperative chemotherapy patient has low white blood cells, it may lead to infection in the patient’s lungs and other tissues, delaying the normal chemotherapy cycle, affecting the patient’s recovery, and even fatal in severe cases. Therefore, although polyethylene glycolized recombinant human granulocyte stimulating factor has some adverse effects, it can effectively enhance the white blood cell count, maintain the body’s immune ability, and improve patients’ quality of life. If necessary, patients can follow the doctor’s instructions to use the drug.