Hemoptysis means an expulsion of blood from the mouth and respiratory tract. Blood is produced during a cough, to a greater or lesser extent. It is sometimes difficult to differentiate with hematemesis, which is coughing up blood from the digestive tract. Hemoptysis is a sign that can lead one to suspect some potentially serious diseases such as tuberculosis, bronchiectasis, or lung cancer. Other lung or bronchial causes are possible, as well as coagulation disorders or pulmonary embolism. After emergency care in the case of significant hemoptysis, an examination to look for the cause must be made including a blood test, chest X-ray, CT scan, or sometimes an endoscopy to view the inside of the respiratory system, if necessary.