High lymphocyte percentage in babies can be seen in normal physiological phenomenon, respiratory tract infection, other diseases, etc. Intervention should be made according to different reasons, such as normal physiological phenomenon without special intervention. 1. Normal physiological phenomenon: between 4~6 days and 4~6 years old, high lymphocyte percentage is a normal physiological phenomenon, for example, between 4~6 days and 1~2 years old, the lymphocyte percentage is about 0.60, and the neutrophil percentage is about 0.35, such as there is no obvious symptom, such as fever, cough or diarrhea, etc, there is no need for special intervention. 2. Respiratory tract infections: acute upper respiratory tract infections, such as nasal congestion, runny nose, or fever and other manifestations, often caused by viral infections, blood routine can show a high percentage of lymphocytes. Treatment should be aggressive and symptomatic, such as the use of antipyretic drugs (e.g., acetaminophen) to reduce fever. When influenza virus infection is suspected, antiviral treatment with oseltamivir phosphate may be used as appropriate. 3. Others: Measles, caused by measles virus infection, may manifest as fever, measles mucous membrane spots and rash, etc., and some of them may be combined with symptoms such as cough, etc., and the percentage of lymphocytes can be seen to be high in perfect auxiliary examination, there is no specific treatment for this disease, and it is mainly symptomatic, such as paying attention to rest, and drinking a lot of water, etc.. All of the above medications should be used under the guidance of a physician, and it is recommended to actively consult a specialist for evaluation and intervention.