High lymphocyte ratio needs to be treated according to the specific disease, including general treatment, drug treatment, radiotherapy and so on. 1. Infectious diseases: Infectious diseases that cause high lymphocyte ratio are mainly viral infections. (1) For self-limiting diseases (e.g. measles, chicken pox, common cold, etc.), general supportive treatment is sufficient, such as taking antipyretic and analgesic medicines (e.g. acetaminophen, ibuprofen) to reduce fever, applying topical glycerine lotion to stop itching, and taking cough medicines (e.g. compound licorice tablets, bromelain, etc.) to stop coughing, as well as to ensure the balance of water and electrolytes. (2) For other more serious diseases, such as viral hepatitis and cytomegalovirus infection, antiviral drugs (e.g. acyclovir, oseltamivir, etc.) should be taken. 2. Blood system diseases (1) Lymphoblastic leukemia: systemic chemotherapy (cyclophosphamide, vinblastine) is the mainstay, while infection prevention, component blood transfusion and nutritional support are needed according to the patient’s condition. (2) Lymphoma: chemotherapy (including doxorubicin, bleomycin, vincristine, dacarbazine) is the mainstay, supplemented by radiotherapy at the site of the lesion. (3) Aplastic anemia: supportive treatment, including prevention of infection, blood transfusion, liver protection, etc., supplemented by immunosuppressive therapy (cyclosporine) and pro-hematopoietic therapy (erythropoietin). If the lymphocyte ratio is high, it is necessary to improve other tests and diagnose the specific disease under the judgment of physicians for targeted treatment.