Any sputum with blood in it, or both sputum and blood, or fresh blood in the whole mouth is called hemoptysis, which refers to bleeding from the trachea, bronchus and lung parenchyma, and blood is coughing out from the mouth. It is the rupture of blood vessels in the respiratory tract or lungs below the larynx, and blood is coughing out of the mouth. Hemoptysis can be divided into blood in sputum, small amount of hemoptysis (less than 100 ml per day), moderate amount of hemoptysis (100-500 ml per day) and large amount of hemoptysis (500 ml or more per day). I. Causes of hemoptysis 1. Bronchial diseases The common ones are bronchiectasis, chronic bronchitis, endobronchial tuberculosis, primary bronchial lung cancer, and bronchial foreign bodies. Less common are benign bronchial tumors, endobronchial stones, bronchial non-specific ulcers, etc. 2. Lung diseases The common ones are tuberculosis, pneumonia, lung abscess, etc. The less common ones are pulmonary stasis, pulmonary infarction, primary or metastatic malignancy, pulmonary cyst, pulmonary fungal disease, pulmonary schistosomiasis, etc. Tuberculosis is one of the most common causes of hemoptysis. 3. Cardiovascular diseases Hemoptysis due to mitral stenosis is more common. Hemoptysis can also occur in certain congenital heart diseases such as atrial septal defect and arteriovenous ductus arteriosus, which cause pulmonary hypertension. 4. Other blood diseases (such as thrombocytopenic purpura, leukemia, hemophilia, etc.); acute infectious diseases (such as pulmonary hemorrhagic leptospirosis, epidemic hemorrhagic fever, etc.); connective tissue diseases (such as polyarteritis nodosa); endometriosis, etc. The significance of concomitant symptoms of hemoptysis 1. hemoptysis with fever Mostly seen in pulmonary tuberculosis, pneumonia, lung abscess, epidemic hemorrhagic fever, pulmonary hemorrhagic leptospirosis, bronchial lung cancer, etc. 2. Hemoptysis with chest pain Most often seen in pneumococcal pneumonia, pulmonary tuberculosis, pulmonary embolism (infarction), bronchopulmonary cancer, etc. 3.Hemoptysis with choking cough Most often seen in bronchopulmonary cancer, mycoplasma pneumonia, etc. 4. Hemoptysis with pus sputum Most often seen in bronchiectasis, lung abscess, cavitary tuberculosis secondary to bacterial infection, etc. 5. Hemoptysis with skin and mucous membrane hemorrhage can be seen in hematological diseases, rheumatic diseases and pulmonary hemorrhagic leptospirosis and epidemic hemorrhagic fever or various causes of coagulation disorders. 6, hemoptysis with pestle finger Most commonly seen in bronchiectasis, lung abscess, bronchopulmonary cancer, etc. 7, hemoptysis with jaundice Leptospirosis, pneumococcal pneumonia, pulmonary embolism, etc. should be noted. Precautions for hemoptysis 1. If hemoptysis occurs, pay attention to it without delay and go to the hospital in time. 2. If the hemoptysis is large, please make sure to keep the respiratory tract open and cough out the blood as much as possible without choking, especially not to block the upper respiratory tract such as the mouth and nasal cavity with handkerchiefs, and go to hospital as soon as possible.