Blood in sputum requires bronchoscopy, lung CT, blood and coagulation tests. Blood in sputum can be seen in lung cancer, bronchiectasis, tuberculosis, pulmonary embolism and emphysema. Coughing up hemorrhagic foamy sputum is usually seen in pulmonary edema, coughing up black bloody sputum is usually seen in pulmonary embolism, coughing up sputum with bright red blood in sputum is usually seen in pulmonary tuberculosis, bronchiectasis and inflammation of the pharynx. Long-term sputum with blood in sputum accompanied by lethargy, fatigue, chest tightness and chest pain is usually seen in lung cancer, and pneumonia can have sputum with blood in sputum accompanied by coughing, coughing up sputum and fever. Bronchoscopy and lung CT are helpful in the diagnosis and treatment of lung tumor, inflammation, bronchial dilatation and tuberculosis, while blood routine and coagulation function tests are helpful in the diagnosis and treatment of pneumonia and pulmonary embolism. If there is any discomfort, it is recommended that patients go to the respiratory department of regular hospitals for consultation and treatment, and should not blindly treat themselves in order to avoid delaying the condition.