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

COLD season is upon us, with coughs, sore throats and runny noses becoming increasingly common. 

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

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

When you’re battling a cold, green snot and phlegm might seem like the norm, however, there are a plethora of shades.

Dr Sarah Brewer, Medical Director for , says the fact you have a runny nose or are coughing up phlegm shows your body is fighting off infection and, hopefully, eliminating it from your body.

She adds: “The colour of your phlegm can reveal how serious your infection is, and if it’s very discoloured or blood-stained, it’s wise to seek medical advice.”

Not feeling ill but still coughing up some phlegm?

Don’t be too concerned 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 by carrying antibodies and immune cells, which help fight off infection,” says Dr Brewer.

So, with adults getting an average of two to three colds per year, here’s what to look out for when you’re coughing and nose blowing, and what the colour of your phlegm can indicate…

Clear 

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

“It means your nasal passages aren’t fighting off a cold.

“It also means that the water, antibodies, enzymes and protein and dissolved salts that make up mucus, can get on with their job – keeping your nasal passages moist.”

White 

This tends to be thicker, and isn’t opaque like clear mucus.

It can often mean the tissues in your nose have swollen up, so that the mucus in your nose can’t move through your nasal passages as quickly as usual.

“It becomes thicker, gloopy, and cloudy because of low moisture 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.

Yellow 

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

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

“The dark yellow, and even green, colour happens when white blood cells rush in to fight infection.”

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

Pink 

Pink phlegm “can be a sign that you have fluid on the lungs”, also known as pulmonary oedema according to Dr Brewer. 

“People with acute pulmonary oedema bring up a very distinctive frothy pink phlegm.”

Pulmonary oedema is essentially too much fluid on the lungs and can also lead to a shortness of breath as well as pink phlegm. 

Heart failure is often a cause of pulmonary oedema. 

Red

Red is the most concerning colour your mucus or phlegm could be. 

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

“It may be caused by coughing, having a chest infection or, sometimes, is a sign of a lung tumour. 

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

“It often happens in older people who smoke.”

Brown

Brown coloured mucus and/or phlegm is most likely to occur if you smoke, especially if you’re a heavy smoker. 

“It can be caused by dried blood from nose bleeds, having a cold, or picking your nose. 

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

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

Black 

Ever left the countryside for the city and found that when you blow your nose, black mucus lands on your tissue?

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

Suffering from a cold?

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

TryEchinaforce Drops (£4.75 for 15ml)

“Good intakes of vitamins A, E, and D are linked to fewer respiratory complaints,” says Dr Brewer, who adds that good nutrition is important in supporting immune health.

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

Zinc and selenium are also required for immunity. Try adding Brazil nuts, seafood, poultry and wholegrains to your diet.

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