Low white blood cell and neutrophil counts in the elderly may be caused by hematologic diseases, drug effects, and viral infections. 1. Blood system diseases: such as aplastic anemia, leukemia, lymphoma and so on. Aplastic anemia causes low hematopoietic function of bone marrow, which can lead to low white blood cell and neutrophil counts; leukemia and lymphoma can also cause low white blood cell and neutrophil counts due to the proliferation of malignant cells. 2. Drug influence: due to lower resistance, the elderly are prone to infectious diseases and thyroid diseases, such as pneumonia, bronchitis, hyperthyroidism, etc. Long-term use of certain drugs can also cause leukocyte and neutrophil counts to be low. Long-term use of certain drugs can also cause low white blood cell and neutrophil counts, such as antibiotics (levofloxacin), antithyroid drugs (methylthiouracil) and so on. 3. Viral infections: Viral infections can cause the proliferation of the lymphatic system, thus causing low white blood cell and neutrophil counts, common diseases include influenza, viral encephalitis and so on. In addition, liver and kidney diseases, poor immune function can also cause low white blood cell and neutrophil counts, you can go to the hospital for further examination to confirm the diagnosis, and then receive treatment under the guidance of the physician after clarifying the cause of the disease.