Neutrophils are a type of white blood cell associated with the phagocytic and digestive functions of the cells. Neutrophil percentage, is the number of neutrophils as a percentage of the total white blood cell count. If it is simply mildly low, most of them have no real clinical significance. If it is accompanied by other symptoms, it is considered to be related to viral infections, disease effects, external influences, etc. 1. Infection causes: certain viral infections, such as influenza virus infection, measles virus, rubella virus; or certain bacterial infections, common ones such as typhoid bacillus, paratyphoid bacillus, and more serious tuberculosis, such as cornual tuberculosis, etc. These infections can cause a low percentage of neutrophils; 2. Blood disorders: diseases of the blood system, such as aplastic anemia, can manifest as a significant decrease in neutrophils. Some malignant diseases such as hemophagocytic syndrome and lymphoma may also have a low neutrophil percentage; 3. Immune diseases: some autoimmune diseases, such as systemic lupus erythematosus itself, produce autoantibodies against white blood cells that can lead to the destruction of white blood cells and make the neutrophil percentage low; 4. Hypersplenism: various causes of splenomegaly can lead to hypersplenism, which destroys The percentage of neutrophils is low; 5. External influences: For example, long-term exposure to X-rays, lead, mercury and other harmful substances, or radiotherapy for cancer patients, may lead to a low percentage of neutrophils; 6. Drug factors: Some antibiotics, antipyretic and analgesic drugs, anti-thyroid drugs or chemotherapy drugs may also lead to a low percentage of neutrophils. percentage is low, but most of them will recover after stopping the medication.