Lung nodules and sputum need to be considered separately. Most sputum is due to chronic inflammation of the airways or acute inflammatory causes. If there is recurrent coughing and sputum, chronic inflammation of the airways needs to be considered, such as whether there is any chronic bronchitis, chronic obstructive pulmonary disease, bronchial asthma and other chronic diseases of the lungs underlying. There are many causes of lung nodules, which are mainly categorized into benign and malignant nodules. Some of the benign nodules are inflammatory nodules, that is, nodules caused by inflammation. Lung nodules require regular follow-up and observation. Some are malignant nodules that require vigilance and need to be evaluated for benignity or malignancy under the formal guidance of a physician as well as formal examination.