Granulation in the lungs may be proliferative tissue caused by tuberculosis, inhalation of a foreign body, infection, or autoimmune disease. 1. Tuberculosis: Tuberculosis is a relatively common disease that can cause granulation tissue, which appears due to the effects of Mycobacterium tuberculosis. 2. Inhalation of foreign bodies: These include talcum powder, etc. When inhaled into the lungs, they can stimulate the lung tissues, leading to the production of granulation and other hyperplastic materials. 3. Infection: mainly refers to bacterial infection, which can cause chronic inflammation of local tissues and gradually form granuloma. 4. Autoimmune diseases: including the common systemic lupus erythematosus, granulomas can also occur. The specific cause of the disease needs to be clarified after medical examination, and follow-up treatment according to the doctor’s instructions.