High-density shadow in the lower lobe of the left lung is considered to be a nodule, which may be benign, such as inflammation or calcified foci in the lung, or malignant, such as malignant tumor, and different treatment options should be chosen depending on the disease. Clinically, the treatment is first according to the inflammation. If there is a significant improvement of symptoms through anti-inflammatory treatment, it means that the diagnosis is confirmed as inflammatory nodules. If the nodules do not decrease after treatment, bronchoscopy should be done to take a biopsy of the lesion for pathological examination and diagnosis, to clarify the nature of the nodules and then confirm the next treatment plan. During the treatment period, you should cooperate with the doctor, drink more water, eat more vegetables and fruits, and pay attention to strictly quit smoking.