Patients with bronchitis can have blood in their sputum because a violent cough can cause localized congestion in the throat and airway mucosa, resulting in blood in the sputum, which is relatively small and does not require antiemetic drugs. Treatment of bronchitis should be carried out only with broad-spectrum antibiotics or antiviral drugs, combined with cough expectorants. After the bronchitis is cured, the symptoms of blood in the sputum will also be improved. However, it is also necessary to exclude the possibility of other lung diseases that cause coughing up blood, including pneumonia, tuberculosis, bronchiectasis, lung cancer, etc. If these diseases are excluded, blood in sputum caused by bronchitis is irrelevant.