What should you know about phlegm cough?

Mucus is made by the lining of the nose, throat, and breathing tubes. Coughing moves it upward so it can be cleared. A common cold or acute bronchitis may cause a temporary increase in phlegm. Allergic rhinitis can allow mucus to drip towards the throat, while asthma can make the airways sensitive and narrow. Acid reflux may irritate the throat and trigger coughing without a chest infection. Persistent daily phlegm deserves assessment because bronchiectasis and other long-term airway problems can also cause it.

The colour or thickness of mucus alone cannot identify its cause. A clinician will consider how long the cough has lasted, whether you wheeze, your breathing, fever, smoking or vaping exposure, medicines, and any medical conditions.

Drink fluids regularly if you can do so safely, avoid tobacco smoke and dusty air, and rest while an infection settles. Warm drinks may soothe an irritated throat. Follow label directions for any pharmacy medicine, and check with a pharmacist if you are pregnant, treating a child, or taking regular medicines. Do not start antibiotics because of mucus colour; they help only some bacterial infections. A cough that continues, keeps returning, or interferes with sleep should be reviewed.

Seek urgent medical help for severe breathlessness, blue or grey lips, confusion, chest pain, coughing up blood, or a sudden marked deterioration. Arrange prompt medical assessment for high fever, worsening wheeze, dehydration, or a cough in someone with significant lung disease or reduced immunity. A clinician can listen to your chest and decide whether tests or treatment are needed.

Ask what may be causing the phlegm, whether your breathing needs testing, which medicines are suitable for you, and what change should prompt urgent review. Take note of the mucus pattern, exposure to smoke or allergens, and any fever or breathlessness.