Lung nodule is mainly a nodular rounded high-density shadow in the lung parenchyma as shown by CT and planar examination. 3mm solid lung nodule is benign in the vast majority of cases, and the chance of malignant transformation is relatively low, so it does not matter in general, and only need to review the CT of lungs on a regular basis to observe whether there is a tendency for the nodule to grow up. However, if the nodules are found to be gradually increasing in size, further relevant examinations, such as enhanced CT and PET-CT, or lung puncture biopsy, etc., are needed to clarify the benign or malignant nature of the nodules before targeted treatment. Patients are advised to eat more fresh vegetables and fruits, such as oatmeal, cabbage, bananas and apples, and avoid strenuous exercise.