Blood when coughing up mucus: what to know

A hard or prolonged cough can irritate small blood vessels in the throat or airways, leaving pink or red streaks in mucus. Airway inflammation, a chest infection, asthma, or bronchiectasis can also cause blood-stained phlegm. Blood from the nose or gums may mix with mucus. Coughing blood is different from vomiting blood; notice whether it comes up after a cough and whether it is mixed with phlegm.

Arrange a clinical review for a first episode, recurrent streaks, or mucus that changes in colour or volume. Take a photo if it is safe and note how often it happens, whether you smoke, and any fever, wheeze, chest pain, or breathlessness. Rest, drink fluids if you can, and avoid smoke. Do not suppress a significant or unexplained cough with leftover medicine.

Seek emergency help if you cough up more than a small streak, the bleeding does not stop, or you have breathing difficulty, chest pain, faintness, blue lips, confusion, or severe weakness. Urgent review is also needed when blood appears with a high fever or rapidly worsening illness. Do not drive yourself if you are breathless or light-headed.

Ask whether the blood is likely from the nose, throat, or lower airways, whether you need a chest examination or imaging, and what changes should prompt emergency care. Mention all medicines that affect clotting.