Phlegm in Your Throat: Causes and How to Clear It

Phlegm in the throat is usually caused by a cold, mucus dripping down from the nose (post-nasal drip), an allergy, acid reflux or smoking. It nearly always clears on its own within days or weeks. Drinking water, salt water nose rinses and steam can help clear it. This guide is by Dr. Pedro Yelamo Vera, an English-speaking GP licensed in Spain (Colegiado No. 484814280) who sees patients by video in English and Spanish.

What is phlegm in the throat?

It is thick mucus. Your nose, sinuses and airways make mucus every day to trap dust and germs. You normally swallow it without noticing.

When there is more of it, or it gets thicker, you feel it in your throat. It can feel like a lump. You keep clearing your throat, and it may cause a cough or bad breath. The NHS calls this build-up catarrh. In Spain people say flemas.

Why do I have phlegm in my throat?

The most common causes are:

• A cold or flu: the most common cause. Phlegm can last a few days longer than the other symptoms.
• Post-nasal drip: mucus from the nose runs down the back of the throat. It happens with sinusitis, hay fever or dry air.
• Allergy: to pollen, dust or pets. You may also sneeze and have an itchy nose or eyes.
• Acid reflux: acid from the stomach rises and irritates the throat. You clear your throat a lot, often in the morning or after meals.
• Smoking and air pollution: they irritate the airways and make more mucus.
• Bronchitis, asthma or COPD: the phlegm comes from the chest and usually comes with a cough.

What does the colour of phlegm mean?

Clear or white phlegm is normal. Yellow or green phlegm is common with a cold. On its own it does not mean a bacterial infection. Read more in our guide to green mucus.

If there is blood, or the phlegm is rust-coloured, always see a doctor.

How do I get rid of phlegm in my throat?

Most phlegm goes once the cause clears. In the meantime, these help:

• Drink water often. Small sips of cold water can clear the throat.
• Breathe in steam, for example in the shower, or use a humidifier if the air is dry.
• Rinse your nose with salt water (saline). It clears mucus that drips down from the nose.
• Gargle with warm salt water.
• Sleep with your head a little raised if you have post-nasal drip or reflux.
• Do not smoke, and keep away from smoke.

A pharmacist can advise on nose rinses and other products. Decongestant nose sprays should only be used for a few days. See our guide to decongestants in Spain.

Why do I have phlegm and a cough?

Coughing is the body's way of moving mucus out. A chesty cough after a cold can last up to three weeks. Read our guide to cough remedies. If it lasts longer, see a doctor.

Can acid reflux cause phlegm?

Yes. If you clear your throat a lot, have a hoarse voice in the morning or a sour taste, reflux may be the cause, even without heartburn. It helps not to eat late, to cut down on fatty food, alcohol and smoking, and to raise the head of the bed. Read about an incompetent cardia and reflux.

Why do I have phlegm without a cold?

If you have no cold and the phlegm lasts for weeks, the likely causes are hay fever, long-term sinusitis, reflux or smoking. A doctor asks about your symptoms, looks at your throat and decides if you need any tests.

What do I ask for at a Spanish pharmacy?

Say tengo flemas en la garganta. You can ask for suero fisiológico or agua de mar for nose rinses. The pharmacist can tell you what suits you.

When to see a doctor

• The phlegm or cough lasts more than 3 weeks.
• There is blood in the phlegm.
• You have a high fever, or a fever for more than 3 days.
• You have chest pain, wheezing or feel short of breath.
• It hurts to swallow, you find it hard to swallow, or you lose your sense of smell.
• You lose weight for no reason or have night sweats.
• You smoke and your cough has changed.

When to call 112

• Severe trouble breathing, or you cannot finish a sentence.
• Blue or grey lips or skin.
• You cannot swallow your saliva and are drooling, especially with a fever.
• You cough up a lot of blood.

Frequently asked questions about phlegm in the throat

Getting a medical assessment

If you are in Spain and have phlegm that will not clear, you can book a video consultation with Dr. Pedro Yelamo Vera, a physician registered in Spain. You can also read about sore throats. A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.

This guide is general information. It does not replace the package leaflet or the advice of your doctor or pharmacist.