Acute bronchitis can potentially lead to coughing up blood. This is because acute bronchitis involves the infection of the bronchi by pathogens such as viruses, bacteria, and mycoplasma, leading to congestion and swelling of the airway mucosa. Patients often exhibit symptoms such as coughing, expectoration, and fever. If coughing is severe, it could rupture small blood vessels, causing symptoms of coughing up blood. If blood is present in the cough, hemostatic treatment is needed. However, not all instances of coughing up blood are due to acute bronchitis. Other possible causes of coughing up blood include lung tumors, pneumonia, tuberculosis, and pulmonary embolism. Therefore, if symptoms of coughing up blood occur, chest X-rays or a chest CT scan should be conducted to confirm the diagnosis.