Lung nodules of 3~5mm are generally not serious, 3-5mm nodules are generally benign, but malignant possibility is not excluded, if malignant, it is more serious. Benign lesions include benign tumors, infections, pulmonary vascular anomalies, etc., which are generally not serious and can be cured after active treatment; malignant lesions include primary lung cancer, metastatic malignant tumors, etc., which are more serious. 1. Benign lesions: If the nodules are infected, anti-infection treatment is the main focus, such as tuberculosis infection, according to the doctor’s guidance of anti-tuberculosis treatment. If the patient has no symptoms, no treatment can be done for the time being, but need to be followed up regularly. If the diameter of the nodule increases and is larger than 8 millimeters, it is considered to have the possibility of malignant changes, and surgical resection is feasible. 2. Malignant lesions: If the nodule is malignant, such as primary lung cancer, metastatic malignant tumor, etc., which may endanger the patient’s life, the patient should be guided by a doctor to make a suitable treatment plan according to the nature of the nodule, the patient’s comprehensive situation, and surgical resection at the earliest possible time. Therefore, if you find lung nodules, you should go to the hospital to find out the cause of the disease as soon as possible and get timely treatment to avoid delaying your condition.