From chest infections to bronchitis: here’s what the color of phlegm means for your health

From chest infections to bronchitis: here’s what the color of phlegm means for your health

COLD season is upon us, with cough, sore throat and runny nose becoming more common.

Experts have already warned that this winter we are likely to see higher rates of flu post Covid too.

Look Inside Your Tissue: Your Mucus Can Tell You a Lot About Your Health


Look Inside Your Tissue: Your Mucus Can Tell You a Lot About Your HealthCredit: Getty

But did you know that the color of your phlegm and mucus can offer some important clues about the state of your health, as well as how your body is dealing with a cold or respiratory infection?

When you’re fighting a cold, green mucus and phlegm may seem like the norm, however, there are a lot of nuances.

Dr. Sarah Brewer, medical director of health lapsesays that the fact that you have a runny nose or are coughing up phlegm shows that your body is fighting infections and hopefully clearing them from your body.

She adds: “The color of your phlegm can reveal how serious your infection is, and if it’s very discolored or bloodstained, it’s wise to seek medical attention.”

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You don’t feel sick but you keep coughing up some phlegm?

Don’t worry too much as it is normal to have some mucus. In fact, mucus actually protects us.

“It does this by keeping our lungs, airways, and nasal passages moist, and transporting antibodies and immune cells, which help fight infection,” says Dr. Brewer.

So, since adults average two to three colds a year, here’s what to look out for when you cough and blow your nose, and what the color of your phlegm may indicate…

Of course

Clear mucus and phlegm are the healthiest. “Clear, runny mucus is a good sign,” says Dr. Brewer.

“It means that your nasal passages are not fighting a cold.

“It also means that the water, antibodies, enzymes, proteins and dissolved salts that make up mucus can do their job: keep nasal passages moist.”


This tends to be thicker and is not opaque like clear mucus.

It can often mean that the tissues in the nose have swollen, so mucus from the nose can’t move through the nostrils as quickly as usual.

“It gets thicker, stickier and cloudier due to low humidity levels,” says Dr. Brewer.

If you cough up white phlegm, it may mean you have an upper respiratory tract infection, such as bronchitis or congested sinuses.


“Mucus and/or phlegm that is thick in consistency and quite dark can mean you have a viral or bacterial infection,” says Dr. Brewer.

“This could be in your sinuses or your lower respiratory tract.

“The dark yellow, and even green, color occurs when white blood cells rush to fight infection.”

Book an appointment with your GP if this colored mucus lasts for more than a few days.


Pink phlegm “may be a sign that you have fluid in your lungs,” also known as pulmonary edema according to Dr. Brewer.

“People with acute pulmonary edema present with very distinctive foamy pink phlegm.”

Pulmonary edema is essentially too much fluid in the lungs and can also lead to shortness of breath and pink phlegm.

Heart failure is often a cause of pulmonary edema.


Red is the most worrying color mucus or phlegm could be.

“If you cough up small amounts of bright red blood, it’s probably from your lungs.

“It can be caused by a cough, a chest infection, or sometimes it’s a sign of a lung tumour.

“If your phlegm is rusty or stained with blood, you should see a health professional urgently,” warns Dr. Brewer.

“It often happens in older people who smoke.”


Brown mucus and/or phlegm is more likely to occur if you smoke, especially if you are a heavy smoker.

“It can be caused by dried blood from nosebleeds, cold or nose picking.

“Brown mucus can also come from air pollution and breathing smoke from a fire,” adds Dr. Brewer.

Brown mucus could also be a sign of pneumonia or old blood. See your GP who can offer advice and guidance.


Have you ever left the country for the city and discovered that when you blow your nose, black mucus falls on your tissue?

Black mucus and/or phlegm can be caused by breathing in dark-colored dirt or dust. “Smoking can also cause black streaks in mucus,” says Dr. Brewer.

Do you suffer from a cold?

Research has found that a traditional herbal cold and flu medicine containing a fresh herb extract of Echinacea purpurea actually reduces the incidence of respiratory tract infections (RTIs).

Try A. Vogel Echinaforce drops (£4.75 for 15ml)

“A good intake of vitamins A, E, and D is associated with fewer respiratory problems,” says Dr. Brewer, who adds that good nutrition is important for supporting immune health.

Enjoy green leafy vegetables, red fruits and vegetables, nuts, seeds and oily fish.

Zinc and selenium are also necessary for immunity. Try adding Brazil nuts, shellfish, poultry, and whole grains to your diet.

A multivitamin and mineral supplement, taken daily, can also help bridge gaps in your diet.

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