Coughing up dark blood: what to know

Blood may look dark after it has remained in mucus or mixed with thicker secretions. A dry nose, irritated throat, forceful coughing and airway inflammation can all introduce blood into what you bring up. The colour alone cannot identify the cause. Acute bronchitis may bring a wet cough after a respiratory infection, and [Bronchiectasis](/conditions/bronchiectasis/) can be associated with recurring mucus and bleeding. Acid reflux can irritate the throat and trigger coughing, while asthma can add wheeze or tightness. These are examples of conditions a clinician may consider; dark blood does not mean that any one of them is present. Vomited blood or bleeding from the mouth can sometimes be mistaken for blood from the airways, so describe exactly what happened.

Stop exertion and sit upright while arranging medical advice. If possible, note the colour, texture and amount, whether it was mixed with mucus, and whether you had nose or gum bleeding. Avoid smoking and avoid vigorous throat clearing. Bring a list of medicines and supplements, particularly anything prescribed to prevent clots, and mention recent infections, travel, injury or a longstanding cough. Do not rely on the dark colour to decide that the episode is harmless. A clinician can examine your mouth, nose and chest and decide whether testing is needed.

Call emergency services if the bleeding is more than a small trace, keeps returning over a short period, or occurs with breathlessness, chest pain, faintness, confusion or severe weakness. Get urgent help for a sudden unexplained cough with blood, especially when one leg is swollen or painful, or when breathing becomes difficult. Arrange prompt clinical review even after a single small episode if the source is unclear. Repeated blood, a cough that persists, or worsening fever should not be watched at home without advice.

Does the appearance suggest older blood or could it be from another source?

What examination or tests would help locate the bleeding?

Should I change any medicine while this is being assessed?