Coughing up blood is commonly seen in bronchial dilatation, tuberculosis, lung cancer, etc. 1. Bronchial dilatation: it often occurs after whooping cough or chronic bronchitis, which deforms and expands the walls of the airways. It can be manifested by repeated coughing, especially coughing up a large amount of purulent sputum in the early morning, sometimes with blood in the sputum. If necessary, high-resolution CT can be done to confirm the diagnosis. 3. Tuberculosis: patients with prolonged low-grade fever, cough and fatigue, emaciation, excessive sweating and other symptoms. The sputum coughed up may have blood in it. 3. Lung cancer: cancerous tissues are rich in blood vessels and prone to tissue necrosis, therefore, lung cancer patients may cough up blood, mostly sputum with blood filaments or intermittent bloody sputum, which is not easy to attract patients’ attention. If invading large blood vessels, it can cause hemorrhage. Coughing up blood may also have other causes, such as pneumonia, systemic hemorrhagic disease, etc. It is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy.