Phlegm, mucus and asthma

Find out what phlegm is and what it could mean if yours is a different colour to usual.

Find out why coughing up more phlegm than usual can be a sign that your airways are inflamed and how to tell one kind of phlegm from another by the colour

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What is phlegm?
Does having phlegm mean my asthma is getting worse?
What does the colour of my phlegm mean?

What is phlegm?

Phlegm is the specific name for mucus that you cough up from your lungs. Your doctor might call it ‘sputum’. And mucus is a jelly-like liquid found all over the body that protects you from infection

Coughing up lots of phlegm doesn't mean you have asthma, although some people with asthma do find they cough up lots of phlegm.  

Does having phlegm mean my asthma is getting worse?

Coughing up more phlegm than usual could be a sign that your airways are inflamed. This means your airways get narrower and this can cause other asthma symptoms, like:

  • coughing
  • wheezing
  • breathlessness.

If you have more asthma symptoms than usual, your reliever inhaler will help open up your airways. But remember, if you’re using your reliever inhaler more than three times a week, you need to see your doctor. 

Taking your daily preventer inhaler as prescribed should help reduce the inflammation that’s causing your asthma symptoms. Find out more about how preventer inhalers help asthma.

Phlegm and asthma

Asthma UK nurse Barbara explains what phlegm has to do with asthma. And what it might mean if yours changes in colour, thickness or amount

Video: Phlegm and asthma

Asthma UK nurse Barbara explains what phlegm has to do with asthma. And what it might mean if yours changes in colour, thickness or amount
Phlegm and asthma

0:07 Gross as it looks phlegm and mucus protect your body from infection.

0:11 A little bit of phlegm is totally normal but if your phlegm

0:18 changes in colour thickness or amount it could be a sign that you're ill and your

0:20 asthma may be affected

0:23 if you find you've been coughing up more phlegm than

0:28 usual this could be a sign that your airways are inflamed this can cause

0:34 asthma symptoms like coughing wheezing shortness of breath or a tight chest

0:38 You should take your daily preventer inhaler as prescribed and it should help stop

0:42 these symptoms because it reduces the inflammation in your airways over time

0:47 if you're doing this and still getting a lot of mucus on your chest you should

0:51 book an appointment with your doctor or ask the nurse

1:00 if you have yellow or green phlegm this might be a sign of an infection like a cold flu or a chest

1:04 infection these can often make asthma symptoms worse so it's really important

1:09 to keep taking your preventer inhaler every day

1:15 if your phlegm is streaked with blood this is usually down to the pressure put on the blood vessels if

1:19 you're coughing a lot the best thing you can do in this case is to see your

1:24 doctor to make sure it's nothing to worry about if you have brown or black

1:28 tinged phlegm it usually occurs in smokers or if you have COPD chronic

1:34 obstructive lung disease as well as asthma when you stop smoking even just

1:40 after three days your Airways will get less inflamed and you'll have less asthma symptoms

1:44 if you want any help or advice you can call the Asthma UK

1:50 helpline and speak to one of the nurses between nine and five Monday to Friday

 

What does the colour of my phlegm mean?

The colour of your phlegm can change when you’re ill.

If you feel unwell and you’re worried because your phlegm’s a different colour or thickness than usual, speak to your doctor. They might look at or test a sample of your phlegm to find out more.  

Everyone’s phlegm looks different and it isn’t a completely accurate guide to what’s going on in your body. But here's a general guide to what different colours of phlegm mean:

White Phlegm

White phlegm

A bit of white or clear phlegm every now and then is completely normal.

However, if you’re producing lots ofwhite or clear phlegm, it could be a sign that your airways are inflamed and your asthma symptoms might be getting worse.

It’s worth remembering that your airways include the nose and sinuses, as well as your throat. It may be that the mucus you’re coughing up has moved from your nose or sinuses to the back of your throat or chest. If you get symptoms in your nose and sinuses – such as mucus, sneezing or an itchy or blocked nose – speak to your GP or pharmacist about how you can treat this. Treating your nose and sinuses can improve your asthma symptoms too.

Your preventer inhaler is the number one way to deal with this, as long as you’re taking it as prescribed by your doctor or nurse.

If you’ve been taking your preventer but nothing’s improving, see your doctor or asthma nurse. They might need to change your medication or help you manage your triggers or allergies, like hay fever

Yellow or green phlegm

This might be a sign of an infection, like a cold, the flu or a chest infection.

Infections often make asthma symptoms worse. This is why it’s really important to keep taking your preventer inhaler every day, as this helps to control your asthma.

Find out how to reduce your risk of catching a cold or the flu if you have asthma. 

White Phlegm

Streaked red phlegm

If you cough up blood, call your GP surgery as soon as possible, even if it's just a tiny bit of blood.

Coughing up blood can be alarming, but it doesn’t necessarily mean there’s a serious problem. If you cough up blood, it is usually because you have been coughing a lot or you have a chest infection.

Read about the common causes of coughing up blood, as well as some less common ones. 

White Phlegm

Brown or black phlegm

There are a few reasons you might get brown or black phlegm and one of these is smoking.

It’s very important that you quit smoking, as it can make your asthma worse in the long term and trigger asthma symptoms in the short term.

Just three days after you’ve stopped smoking, your breathing will become easier and you'll have more energy. Get help to quit smoking.

Coughing up brown phlegm can also be a symptom of pneumonia. If you’re coughing up brown or black phlegm, it's really important that you book an appointment with your GP. 

Last updated November 2020

Next review due November 2023 

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