The severity of multiple ground glass nodules in the lungs cannot be generalized. The etiology varies and so does the severity. The specific analysis is as follows. 1. benign lesions. (1) Pneumonia: Infectious multiple ground glass nodules caused by bacteria, fungi, viruses, tuberculosis and other pathogens, the nodules can partly disappear after anti-infective treatment or anti-tuberculosis treatment, and most of them are not serious. (2) Acute stage of allergic pneumonitis: it can be manifested as multiple ground-glass nodule shadows, which can be relieved after detaching from allergens and glucocorticoid treatment; if there is no timely treatment or the condition progresses, there is the possibility of respiratory failure and other serious complications. (3) Lung hemorrhage: lung hemorrhage can cause multiple ground-glass shadows, and a small amount of hemorrhage can be completely absorbed after treatment. (4) Diffuse interstitial fibrosis: it can cause multiple ground-glass shadows, and requires glucocorticoid and immunosuppressant treatment, and is generally more serious. (2) Lung cancer: diffuse alveolar carcinoma or metastatic carcinoma of other tumors may appear multiple ground glass nodules in the lungs, which is more serious and needs lung tissue biopsy to clarify the pathology of the tumor for further anti-tumor treatment, and the prognosis is poor, and the advanced stage may be complicated with multiple organ failure. Most of the multiple ground-glass nodules found in lungs are not serious, and it is recommended to seek timely medical treatment under the guidance of specialists to clarify the cause of the disease and treat the cause.