Hemorrhagic pleural effusion may be caused by trauma, or it may be caused by tuberculosis, malignant tumor and other diseases. 1. Trauma: If the patient’s chest has suffered a car accident or other violent impact and other traumatic injuries, it will cause the patient to develop pleural hemorrhagic effusion. 2. Tuberculosis: Tuberculosis is caused by Mycobacterium tuberculosis infection, when the tuberculosis invades the pleural blood vessels and causes the rupture of blood vessel wall, bloody pleural cavity effusion can occur. 3. Malignant tumor: malignant tumors are mainly caused by long-term effects of many factors, if a part of the patient’s body or organ has malignant tumors, and the phenomenon of thoracic metastasis, it will also lead to the emergence of pleural hemorrhagic effusion. When the patient has a pleural hematochezia, he should go to the hospital in time, clarify the cause of the disease, and take specific treatment measures under the guidance of the doctor.