Phlegm Colour says a lot about digestion and health

What does the colour of your phlegm say about your health? Burning too hot to too cold? OR something else?
Qi Stagnation book cover
You can learn more about Qi Stagnation and stress in our book on stress.
Knitting Balls

Key Learning Points

  • Where the phlegm colour comes from
  • What its consistency means
  • And its smell
  • And the circumstances causing it

Before going into what phlegm colour means, phlegm is a major syndrome in Chinese medicine.

You can read more about it here, explaining why it can be such a nuisance.

I’ve also written a book about it: see my YouTube video for more:

What does your phlegm colour say about your health? And what does this mean from the point of view of Chinese medicine?

More important, what does Chinese medicine suggest you do about it?

I hope you’ll find this page useful, but if you want more information, a lot more!, I’ve written a book “Yuck! Phlegm!” about the best ways to deal with each kind of it, including an analysis of many of the different suggestions made elsewhere on the web: what works and what won’t work – and why it won’t work.


Vital Fluids eg mucus

Your organic bodily fluids are vital for your health, in Chinese as much as Western medicine. These fluids are the oil that keeps your body moving smoothly. They moisturise it, inside and out, they cool it, they carry nutrients to it and waste away from it.

Where are they made? According to Chinese medicine, they arise from your Stomach and Spleen energies working on what you eat and drink (not really so different to Western medicine!).

How they are filtered, purified and separated comes under other energy organs (zang-fu is the correct term), but they start with your Stomach and Spleen.

So what you put down your throat is your first step, for better or worse. As they say, ‘food is your first medicine’.

In Chinese medicine, you can sometimes alter the colour of your phlegm by eating different foods, if you go on for long enough. I don’t mean that if eating something purple, like beetroot, you clear your throat and inspect the phlegm to find it’s purple. I mean that foods have energetic effects – which means some foods have a cold energy and some have a hot energy.

Equally, if you go on for long enough, you can often improve your phlegm colour with the right nutrition.

Often, but not always. The colour of your phlegm depends on other things too, like what syndromes or factors are affecting your health. Two big factors are Heat and Cold.


How do Heat and Cold first affect you?

Heat and Cold affect your health by ‘invading’ you! Specifically, they enter by overcoming your body’s defences. In reaction, your body produces symptoms, which are its way of dealing with the problem.

They demonstrate where your body has put the problem: in particular, how far away from your vital ‘core’ it is maintaining the ‘dis-ease’.

Those symptoms are described in Chinese medicine according to a well-developed theory which goes back at least 3000 years.

Acute reactions often come in one of two forms:


Ongoing disease can do it too

Your body has a whole set of genetic or inherited templates to use when confronted by different diseases. They give it a huge range of solutions. Your symptoms show how your body is using its resources the best way it knows how.

Modern medicine has ways to ease the pain of these genetically inherited solutions, but if you read my page on Suppression, you’ll understand perhaps why sometimes you are better off allowing your body to deal with the problem its own way.


Fire suppression equipment. Phlegm colour often shows symptom suppression.
Painting equipment for the prevention and suppressID 20542298 © Chatchai Somwat |


For example, if your body can clear the disease its own way, you don’t usually get stuck with what is called a ‘remaining pathogenic factor‘ which often follows the use of modern medicines like antibiotics.

Anyway, diseases (ie, your body’s best responses) can change your phlegm colour.

These diseases can be acute or chronic. Chronic means that your body has given up trying to expel the disease (an acute reaction being its first line of defence), and has been forced to allow the disease to penetrate inwards to a deeper level where, with luck, it can ‘hold’ it.

But … this means it (ie you!) has to learn to live with it.

Acute diseases last a few days or, at most, weeks. Chronic diseases can last as long as you do, in theory, unless you get help and/or make a huge change in your life.

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Where your phlegm/mucus appears from

Where your phlegm appears from makes a difference.

  • It is normal and healthy to have saliva in your mouth – that’s a normal kind of mucus
  • your internal organs, muscles and joints are separated from one another by soft flexible sheets of connective tissue (‘fasciae’) that slide smoothly past one another via the presence of oily fluids: not phlegm – but body fluids. When these dry out, as in pleurisy, for example, you can’t breathe without inflammation and pain. Inflamed, arthritic joints often lack enough body fluids.
  • pus emerging from a spot or boil on your skin indicates a longer process during which your body has kept its problems on the outside – usually a healthy reaction, even if painful and unsightly. But this is not phlegm as meant on this page.
  • vaginal fluids naturally change in colour and consistency through the menstrual cycle
  • overnight, during sleep, the mucus in your throat and lungs may ‘cook’ slightly, thickening it and producing slightly coloured mucus which you spit out in the morning. That’s phlegm: ideally you shouldn’t have it. Its presence makes you potentially susceptible to more serious conditions because, for a start, its presence impedes the free movement of Qi in your Lungs. That reduces your energy – very slightly – making your immune system less effective.
  • thick, coloured phlegm which you cough up suggests to your doctor an infection and to your acupuncturist a syndrome such as Lung Phlegm Heat. For more about this see Cough.
  • NB This page is mostly about phlegm from your lungs or throat or nose, although the theory applies to other body areas too.


Phlegm Colour

The more energy your body puts into defending itself, the more ‘vital’ will be your symptoms, including your phlegm colour.

‘Vital’ means full of life, which in the case of phlegm colour means vibrant, not perhaps an adjective you’d use normally but

  • brightly coloured, either green or yellow or red, which usually mean your body is applying Heat.


The less energy it has to put into defending itself, or the more chronic its condition, the less coloured will be the  phlegm:

  • white or clear phlegm colour usually means either an absence of Heat or the presence of Cold.


Dark-coloured phlegm

The longer it has been cooking it, the darker will be the phlegm colour. So brown, even black, suggests a more chronic condition.

That brown or black phlegm might have been any colour before it cooked.  However, just as when you leave a stew cooking on the hob for too long and find charcoal when your return to it, so has your body been cooking your mucus!

Brown or black is not a healthy phlegm colour.

Do remember that what you have recently eaten may colour your phlegm: this discolouration soon disappears, however. It is harmless.

Darker phlegm colours mean that your body has had phlegm for some time. It is trying to clear it with heat, but, just as charcoal in your saucepan stuck to the bottom of the pan can’t be shifted by applying extra heat, so also with your body. Your body can only clear this black stuff by hawking it up and out. It’s hard to shift. Probably some remains. 


Phlegm Density

Phlegm Colour is one thing. What the phlegm looks like is another!

The denser the phlegm, either the greater the Heat applied to it, or the longer it has cooked.

Just like on your stove, if you turn up the heat on a soup you are making, it will become thicker. Or you could put it on low, forget about it, and then be reminded only too late by the smell of burning, at which point the fluids have boiled away, leaving just solids, which quickly carbonise.

So, thick lumpy or stringy phlegm has been cooking for longer.

  • The more coloured it is, the more Heat there has been in forming it
  • The less coloured it is, the longer it has been cooking or has been cooking without much Heat
  • If watery, it suggests what is called a deficient condition, possibly with the presence of Damp-Cold
  • If thick, it suggests either more heat, such as Damp-Heat, or a longer period of ‘cooking’. This is a more excess cond

Smell or odour of Phlegm/mucus

  • If fishy, it means Lung Heat
  • If leathery, like old saddles, it suggests Heat
  • ‘Rotten’ suggests Lungs-Heat, ie Heat in the Lungs, probably Lungs Phlegm-Heat, perhaps with Toxic Heat’ (Sorry – no page on this yet, either).
  • If it has no smell, then probably Cold predominates


If phlegm/mucus is clear and watery


House in the snow: Cold makes phlegm thicker and clearer or sometimes more opague
Photo by Greg Rakozy on Unsplash


This is a sign of Cold. What does this mean? One or more of the following might apply:

  • Your body’s Yang energy is low, specifically the yang of your Stomach and/Spleen, but, if you always have lots of clear watery mucus or phlegm, probably other Yang energies are low too, such as that of your Kidney Yang
  • Cold-Damp
  • You have just eaten/drunk a lot of food/fluid that is cold to the touch, or has a cold energy


Why might you have clear, watery phlegm/mucus?

  • You are cold or have entered a cold environment 
  • Recently you caught a disease to which your body responded not with heat but with cold: this is called an ‘invasion of Cold’, such as occurs with Wind-Cold
  • you have recently eaten or drunk more cold or iced food/fluid than your stomach can handle – see Cold Foods
  • Are you wearing enough for your environment?
  • You don’t take enough exercise to warm you up and burn away the cold


If you always have mucus that is clear and watery, ie chronic:

  • While growing up, you were often cold or wore too little
  • you have recently had an acute, exhausting, illness
  • as an adult, you regularly wear too little and are often cold
  • you are growing old and your energy is running down
  • perhaps you are vegetarian and never eat warm food, let alone meat and other foods classified in Chinese medicine as Warming
  • you are vegetarian and always eat food that is raw or classified as ‘cold
  • it is late in the day and you are tired
  • you don’t wear enough to cope with 

What if phlegm colour is white?

White phlegm and sputum (especially if sticky) suggests not that you have great Yang deficiency, but that your Spleen and Stomach Qi are deficient. This produces, together with Kidney Yang deficiency, a condition called Cold-Phlegm’

  • You may be eating too many raw or cold foods
  • Possibly you are eating too much sweet or dairy food (= from cows)
  • You may be eating too many very rich or fatty foods (although heating, these may hamper your Spleen energy from digesting food properly, so might not yet cause signs of Heat)
  • Probably your digestion is not receiving the respect it deserves
  • You may be eating too fast. Read Nutrition and reflect on how to eat in a relaxed, unhurried way, chewing well.
  • The white colour also occurs after taking antibiotics for an infection. Here the colour (produced by your body’s Heat reaction to the disease) has been reduced or removed, but an underlying problem remains. (Thank heavens for antibiotics, they’ve save many lives, but we have been overusing them, so read Suppression.)


Where does white mucus come from?

White mucus is typically coughed or hawked up or appears in your nose.

White mucus or phlegm colour appears

  • when your body is slightly under-functioning and/or
  • you are misusing your body’s energy


You can help yourself by

  • eating better – read Nutrition
  • taking more vigorous exercise, enough to get you out of breath for at least 20 minutes daily
  • keeping warm – not least in bed when asleep – but when exposed to cool environments
  • getting enough good sleep
  • doing deep breathing
  • eating more Hot foods
  • eating less Cold Foods


White mucus is a step towards other forms of phlegm. It easily obstructs normal bodily processes and can become heated, leading to more highly coloured forms of phlegm (for example, yellow or green) with the additional problems they bring.

Try to clear white mucus before it changes to something worse!

What if phlegm colour is yellow?


Yellow Cake
Photo by Andrea Lightfoot on Unsplash


The phlegm colour yellow indicates Heat. It might be a lot of heat, or only a little. The thicker, more sticky, more colourful, stronger-tasting or more smelly it is, the more heat.

Where has this heat come from?

  • If from an acute infection – probably a form of Wind-Heat
  • From an internal syndrome


What kind of internal syndrome?

  • One of the many kinds of Phlegm-Heat. These can occur in: 
  • the upper part of your body, such as in Lung-Phlegm-Heat, or  
  • the middle part, below your diaphragm but above your belly-button, such as Gallbladder Damp-Heat or
  • in the lower part of your body, inferior to your belly-button, such as occurs in Damp-Heat in your Lower ‘Burner’
  • Note: eating the sweet, sticky custard cake in the picture won’t help, not because it is yellow, but because it is heating(And yes, I enjoyed it, with a coffee. But I was on holiday.)


What if the phlegm colour is purulent?

‘Purulent’ phlegm colour means containing pus. This may be yellow or yellow-green. The pus might contain blood, making it red.

Purulent phlegm colour is a step further down the scale from cold to hot, and indicates – if from the lungs – ‘Lungs Toxic Heat’.


What if phlegm colour is green?


Phone box under ivy. Vibrant green-phlegm-colour suggests something growing or developing, overcoming the body's defence.


Green phlegm colour is usually a warmer version of yellow phlegm.

But not always:it could just be older. It depends on the vibrancy of the colour. The more vibrant the colour the more it suggests Heat and an active Phlegm-Heat or Damp-Heat syndrome. By ‘active’ I mean developing, growing, like the ivy in the picture above. For example:


Red phlegm colour


Burning Firewood
Photo by Luke Porter on Unsplash


A red phlegm colour contains blood. Escaped blood means either that there is excess Heat or, occasionally, that there is Yin deficiency.

Or both, as may occur, for example, in end-stage tuberculosis.


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