Hemoptysis in young adults is commonly associated with pulmonary tuberculosis, bronchiectasis, mitral stenosis, etc. A history of long-term smoking (20 paper cigarettes/day x 20 years) over the age of 40 years should be highly relevant to the possibility of bronchopulmonary cancer. Children with chronic cough with small amounts of hemoptysis and hypochromic anemia should be aware of the possibility of idiopathic iron-containing hemoglobinosis. What diseases can hemoptysis with skin and mucous membrane bleeding be diagnosed as? 1. Hemoptysis with fever: Most commonly seen in tuberculosis, pneumonia, lung abscess, epidemic hemorrhagic fever, pulmonary hemorrhagic leptospirosis, bronchopulmonary carcinoma, etc. 2. Hemoptysis with chest pain: mostly seen in pneumococcal pneumonia, pulmonary tuberculosis, pulmonary embolism (infarction), bronchopulmonary cancer, etc. 3.Hemoptysis with choking cough: mostly seen in bronchial lung cancer, mycoplasma pneumonia, etc. 4. Hemoptysis with pus sputum: mostly seen in bronchiectasis, lung abscess, cavitary tuberculosis secondary to bacterial infection, etc. Among them, dry bronchiectasis only shows repeated hemoptysis without pus sputum. 5. Hemoptysis with cutaneous mucosal hemorrhage: it can be seen in hematological diseases, rheumatic diseases and pulmonary hemorrhagic leptospirosis and epidemic hemorrhagic fever, etc. 6. Hemoptysis with pestle finger: mostly seen in bronchiectasis, lung abscess, bronchopulmonary cancer, etc. 7. Hemoptysis with jaundice: Leptospirosis, pneumococcal pneumonia, pulmonary embolism, etc. should be noted. There is no clear definition of the criteria for the size of hemoptysis, but it is generally considered that hemoptysis within 100 ml per day is a small amount, 100-500 ml is a medium amount, and more than 500 ml or one hemoptysis of 100-500 ml is a large amount. Large amounts of hemoptysis are mainly seen in cavitary tuberculosis, bronchiectasis and chronic lung abscess. Bronchopulmonary carcinoma rarely has large hemoptysis, which is mainly manifested as blood in sputum and is continuous or intermittent. Chronic bronchitis and mycoplasma pneumonia may also present with blood in sputum or bloody sputum, but are often accompanied by a violent cough.