Ground-glass shadows in the lower lobes of both lungs may be caused by tuberculosis, interstitial fibrosis, lung infections and lung cancer. 1. Tuberculosis: Tuberculosis is generally a chronic infectious disease caused by mycobacterial infection, which can be manifested as foci in the lower lobes of both lungs, and the patient may have symptoms such as night sweats, fatigue, poor appetite, and emaciation. 2. Interstitial fibrosis: Interstitial fibrosis is a respiratory disease characterized by inflammatory damage and destruction of tissue structure, which is usually caused by smoking and environmental factors, etc. Patients may have dry cough without sputum, shortness of breath and other symptoms. 3. Lung infection: lung infection usually refers to the inflammation of alveolar cavity and terminal airways, usually caused by bacterial infection and viral infection, etc. Patients may have cough, sputum, fever and other symptoms. 4. Lung cancer: Lung cancer generally refers to primary malignant tumors of lungs, which is usually related to smoking and air pollution, etc. Patients may have symptoms such as low-grade fever, chest pain and tightness of breath. Finding ground-glass shadow in the lower lobe of both lungs should go to the hospital and be treated under doctor’s guidance.