What should you know about black sputum?

Sputum can pick up dust, soot, smoke, or other particles from the airways. A dark brown or black appearance may also reflect older blood mixed with mucus. Infections such as acute bronchitis or pneumonia can change phlegm, while bronchiectasis and COPD may cause ongoing mucus and airway irritation. Mucus draining from chronic sinusitis can also be coughed up and mistaken for material from the lungs. Colour alone cannot identify the cause.

Take a clear note of the colour, thickness, smell, amount, and how long it has lasted. Mention smoking, vaping, workplace dust, mould, recent travel, fever, chest pain, and any blood streaks. Drink fluids if you can, avoid smoke and dusty air, and do not start leftover antibiotics. A clinician may listen to your chest and decide whether a sputum sample or imaging is appropriate.

Get emergency help for severe breathlessness, blue or grey lips, confusion, fainting, chest pain, or more than a small amount of blood in sputum. Arrange prompt review if black sputum persists, returns, has a foul smell, or comes with fever, night sweats, weight loss, wheezing, or worsening cough. People with known lung disease should use their clinician's action plan and seek help earlier if symptoms are changing.

Ask whether the mucus appears to come from the nose, throat, or lower airways; whether your exposure history suggests irritation; and whether you need assessment for infection, bronchiectasis, COPD, or another lung problem.