Tuberculosis can be contagious when coughing up blood. Tuberculosis is a lung disease caused by Mycobacterium tuberculosis infection, and is a Class B infectious disease. Patients with tuberculosis can often cough up blood, either with blood in the sputum or with moderate to large amounts of hemoptysis. During hemoptysis, it generally indicates that the tuberculosis is in a progressive stage and not under control, so it may be contagious and needs to be treated in isolation. If the cough, fever and hemoptysis improve after a period of anti-tuberculosis treatment, the infectiousness of the patient can be greatly reduced. During the treatment of tuberculosis, it is necessary to pay attention to the toxic side effects of drugs on liver and kidney functions and blood system, etc. It is necessary to review the liver and kidney functions and blood tests regularly.