What should you know about coughing up thick phlegm with blood?

Thick sputum can be harder to clear, so repeated coughing may irritate the airway and leave streaks of blood. Pneumonia can cause heavy mucus alongside fever, chills or chest pain. Bronchiectasis is associated with persistent sputum and can bleed during a flare. A clinician may also consider pulmonary embolism, tuberculosis or lung cancer when symptoms, history and examination point in those directions.

Compare the sputum with your normal pattern: note its colour, smell, amount, consistency and how often blood appears. A description of associated symptoms is more useful than colour alone.

Seek prompt medical advice and mention any lung disease, recent infection, smoking, travel or medicine that affects clotting. Sip fluids if you normally can, rest upright and avoid smoke. Do not delay assessment by trying to produce more sputum. Avoid starting antibiotics without a prescription because thick mucus has several possible causes.

Use emergency services if you develop sudden or severe breathlessness, sharp chest pain, faintness, confusion, blue lips, or bleeding that is heavy, repeated or worsening. Arrange same-day care if fever and weakness are increasing, the blood does not stop, or you cannot clear the mucus. Do not drive if you feel faint or short of breath.

Ask whether your sputum needs testing, whether a chest examination or scan is appropriate, how to clear mucus safely, and which changes mean you should return urgently.