Rupture of capillaries on the surface of the alveoli leading to bleeding is a serious disease. There will be many capillaries on the surface of the alveoli, all of which perform important functions, such as performing gas exchange and nourishing lung tissue. The common cause of alveolar hemorrhage is infection of the lung tissue, i.e. inflammation of the bronchopulmonary tissue can cause bleeding in the alveoli. There may also be circulatory causes, such as pulmonary thromboembolism, or cardiac insufficiency, which can cause rupture of capillaries on the surface of the alveoli, leading to bleeding. Therefore, alveolar hemorrhage is a clinically serious symptom that requires prompt medical attention. It is important to pay attention to it and go for relevant examinations to find the cause of alveolar bleeding, and not to be sloppy and careless.