Phlegm, mucus and catarrh: what is the difference?
Your nose, sinuses and airways make mucus all the time to trap dust and germs. When the lining is irritated by infection, allergy, smoke or reflux, it makes more, and it becomes thicker. Mucus from the nose and sinuses is often called catarrh; when it collects in the throat or is coughed up from the chest it is usually called phlegm or sputum. Phlegm in the throat is frequently mucus that has dripped down from the back of the nose, known as postnasal drip.
Common causes
- Colds and flu: the most common reason, with clear then thicker mucus for one to three weeks.
- Sinusitis: thick mucus with facial pressure and a blocked nose.
- Chest infections: bronchitis or pneumonia, with a productive cough and sometimes fever.
- Allergies and non-allergic rhinitis: ongoing clear mucus and throat clearing.
- Reflux: stomach contents reaching the throat can cause a sensation of mucus; see laryngopharyngeal reflux.
- Smoking and vaping: irritate the airways and increase mucus.
- Long-term lung conditions: asthma, COPD and bronchiectasis.
How to get rid of phlegm in your throat
- Drink enough fluids: water, warm drinks and broths keep mucus thin.
- Gargle with salt water: half a teaspoon of salt in a glass of warm water, several times a day.
- Rinse the nose with saline: sprays or rinses clear mucus at its source and reduce postnasal drip.
- Use steam: a hot shower or a bowl of hot water (adults only, carefully) loosens mucus.
- Swallow or cough gently instead of constant throat clearing, which irritates the throat and creates more mucus.
- Raise your head at night with an extra pillow to reduce mucus pooling in the throat.
- Treat the trigger: allergy control, reflux measures or stopping smoking.
How to get rid of phlegm in your chest
- Stay active: walking and moving around help shift mucus from the lungs.
- Controlled coughing: sit upright, take a slow deep breath, hold for two to three seconds and give two short coughs.
- Huffing: breathe in, then breathe out forcefully through an open mouth as if steaming a mirror; repeat a few times then cough.
- Steam and humidified air can make mucus easier to bring up.
- Lying on your side or slightly head-down can help drainage in some people; ask a physiotherapist if you have a lung condition.
- Honey and lemon in warm water can soothe a cough in adults and children over one year.
- Avoid cough suppressants for a productive cough unless a doctor advises them; coughing up phlegm is useful.
Medicines that may help
Guaifenesin is an expectorant sold over the counter that may thin mucus, although evidence for its benefit is modest. Saline nasal sprays are safe for most people. Decongestant sprays should not be used for more than a few days. Antibiotics only help bacterial infections such as some cases of pneumonia; most phlegm after a cold is viral and does not need them. People with asthma or COPD may need their usual inhalers adjusted. Ask a pharmacist before combining cold remedies, as many contain the same ingredients.
What the colour of phlegm means
- Clear or white: common with colds, allergies and irritation.
- Yellow or green: shows that immune cells are present; it happens with viral and bacterial infections and does not by itself mean you need antibiotics.
- Brown: may be old blood or, in smokers, tar; mention it to a doctor if it persists.
- Pink, red or streaked with blood: see a doctor; coughing up more than a small streak needs urgent assessment.
- Frothy: may occur with fluid on the lungs, especially with breathlessness; seek medical advice.
When to see a doctor
- Phlegm or a cough lasting longer than three weeks.
- Coughing up blood.
- Breathlessness, wheezing or chest pain.
- A high temperature or feeling very unwell.
- Weight loss, night sweats or hoarseness lasting more than three weeks.
- Frequent chest infections or daily phlegm, which may indicate a lung condition.
Key points to remember
- Most phlegm clears as a cold or infection settles.
- Fluids, steam, saline, movement and good coughing technique help.
- Colour alone does not tell you whether you need antibiotics.
- Blood, breathlessness or phlegm lasting over three weeks need a doctor.
Questions about phlegm
These answers are general information and do not replace an examination or individual medical advice.
Why do I always have phlegm in my throat?
Constant throat phlegm is often due to postnasal drip from rhinitis or sinus problems, reflux, smoking or dry air. Treating the underlying cause works better than repeatedly clearing the throat.
How can I get rid of phlegm at night?
Raise the head of the bed, use a saline rinse before bed, keep the bedroom air from becoming too dry, drink fluids during the day and avoid eating late if reflux is a factor.
Should I spit out or swallow phlegm?
Either is fine. Swallowed phlegm goes to the stomach and is harmless. Spitting it out lets you notice changes in colour or blood.
Does milk make phlegm worse?
Studies have not shown that milk increases mucus production, although some people feel it coats the throat. There is no need to avoid it unless you notice it bothers you.
How long does phlegm last after a cold?
Usually one to three weeks. If it lasts longer, or you have other symptoms, see a doctor.
Sources
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.