What should you know about black cough?

Dark sputum can follow exposure to smoke, dust, soot, or other airborne particles. Mucus may also look brown or black after it collects inhaled material. A small amount of old blood can appear dark, while fresh blood is often bright red or pink.

Cough may accompany a common cold, acute bronchitis, asthma, allergic rhinitis, or acid reflux. Longer-lasting or mucus-producing cough can also occur with chronic cough or bronchiectasis. In a young child, breathing symptoms need particular attention because bronchiolitis can worsen quickly.

Move away from smoke, dust, and fumes, and drink fluids if you can do so safely. Note the sputum colour, amount, smell, and how long it has appeared. Arrange medical review if the dark material persists, returns without an obvious exposure, or comes with fever, chest discomfort, wheezing, or breathlessness. Do not smoke or vape while waiting for advice.

Call emergency services for coughing up more than a trace of blood, difficulty breathing, blue or grey lips, severe chest pain, fainting, confusion, or rapidly worsening symptoms. A child who is struggling to breathe, feeding poorly, or unusually sleepy also needs urgent help. Dark sputum after smoke exposure still warrants assessment when breathing is affected.

Ask whether the colour suggests inhaled particles, infection, or blood; whether you need a chest examination or imaging; and whether reflux, asthma, bronchiectasis, or another airway condition fits your pattern. Share smoking history, workplace exposures, and every medicine you use.