Phlegm Colour says a lot about digestion and health

What does the colour of your phlegm say about your health? Burning too hot or too cold? OR something else?
Knitting Balls

Key Learning Points

  • Where phlegm colour comes from eg brown phlegm, white phlegm, clear phlegm, green phlegm or grey phlegm
  • What phlegm consistency means
  • And its smell …
  • And how you got it!

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

By the way … many other words also mean phlegm! For example,

  • catarrh,
  • sputum,
  • spit,
  • flems,
  • snot,
  • spittle,
  • discharge
  • but notMUCUS‘ which is a natural and necessary fluid in your body – see below.


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

I’ve also written a book about it: see my YouTube video (below) 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

brown snail on green leaf: snails need mucus, like us!
Snails travel on mucus. We use wheels – and feet! Photo by Raphael Renter

Your organic bodily fluids are vital for your health, in Chinese as much as in 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.

So, to be pedantic, mucus is healthy, though we often use the word to mean phlegm, which is thicker and more chronic, appearing in your sinuses, throat, lungs and stomach.


But when you spit it out, it becomes sputum.


For more on phlegm meaning, read my page on it.


On this page, to make searching easier, we often use the word ‘mucus’ if that’s what we know you search for.


If you have a cough with mucus or phlegm, besides this page and the one on ‘phlegm’, also read our page on ‘cough’.


Where are these fluids made? According to Chinese medicine, they start from your Stomach and Spleen energies – in effect, your digestion – 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 and, more specifically, often from Stomach and Spleen deficiency.

Your First Medicine! So … What went down your throat?

woman with messy hair wearing black crew-neck t-shirt holding spoon with cereals on top
The wrong food creates phlegm. Photo by Tamas Pap

So what you put down your throat is your first step, for better or worse, to understanding this.

As they say, ‘food is your first medicine!’

Well, food is also your first POISON!

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 in the short-term, such as immediately after eating something purple, like beetroot, when you clear your throat and see your phlegm is purple! Here, just wait a few minutes or have something else to eat and your phlegm colour will revert to normal.

I mean that foods have energetic effects – which means some foods have a cold energy and some have a hot energy. Because these foods have different energies they’ll tend to produce different kinds – and colours – in your phlegm.

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 in Chinese medicine. 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.

woman in brown and white tribal coat holding white ceramic mug
Hot and Cold drinks help balance us. Photo by Anthony Tran

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, described in detail about 2500 years ago.

Acute reactions often come in one of two forms:


Chronic reactions take longer to develop and, being chronic, don’t easily go. That you have ongoing phlegm means – nearly always – that your condition is chronic. Why? To find out, you should read our page on phlegm. (Just some examples … it could be due to poor eating habits and nutrition, digestive problems or stress.)

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 options. 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 why sometimes you are better off letting your body deal with the problem its own way.


Fire suppression equipment. Phlegm colour often shows symptom suppression.
Painting equipment for the prevention and suppression of problems © 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 and prevent it going deeper.

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.

Play Video

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 and isn’t ‘phlegm’: this is sometimes wrongly called ‘clear phlegm’, but there’s more on ‘clear phlegm’ proper below
  • 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: again, 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.
  • healthy vaginal fluids naturally change in colour and consistency through the menstrual cycle: not ‘phlegm’.
  • 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, such as from your stomach.

multicolored flower illustration

Phlegm Colour

The more energy your body puts into defending itself, the more ‘vital’ (meaning ‘energetic’) 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 normally use for this but

  • brightly coloured, either green or yellow or red, 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 phlegm or clear phlegm colour usually means either an absence of Heat or the presence of Cold. It could also mean the lack of enough energy to do anything about it!


Dark-coloured phlegm, brown phlegm, grey phlegm, black phlegm

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

That brown, grey 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. Long-term smokers often have dark phlegm, coloured by the soot in their lungs.


red heart shaped decors on pink wall: beetroot turns phlegm colour purple
Purple food gives you purple phlegm! Photo by FOODISM360

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.

Black phlegm

Black phlegm may not be phlegm, but old blood, just as a blood clot slowly darkens until, almost black, one day your body discards it.

Obviously you’ll worry that this dark blood points to cancer but it doesn’t always. It could be an ulcer, and you should still see a doctor.

Before panicking, read our page on Stomach Blood stasis.

Grey phlegm

Grey phlegm is most likely white phlegm discoloured by something you’ve eaten or inhaled. If so, it should disappear after a few hours.

Otherwise, it’s been going through a darkening process caused over time by heat, as explained above. If that’s the case, it’s a slow process, so not usually acutely serious, but if it persists, you should see an acupuncturist or your doctor.

Phlegm Density

Phlegm Colour is one thing. What its consistency 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 such as Spleen Damp Cold
  • If thick, it suggests either more heat, such as Damp-Heat, or a longer period of ‘cooking’. This is a more excess condition
Jonathan Brand colours

Stay in Touch!

No spam, only notifications about new articles and updates.

The latest books
Book a Consultation
Book Consultation
Acupuncture consultation

Book a Video consultation if you want to know more about your symptoms

Smell or odour of Phlegm/catarrh

  • 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).
  • If it has no smell, then probably Cold predominates or you have yang deficiency

If phlegm/catarrh is clear and watery: ‘clear phlegm’


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:

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
  • In Western medicine, assuming other symptoms that help in diagnosis, you could have allergic rhinitis, or early stage bronchitis or early stage pneumonia. With the last two you’d also have a cough with the phlegm. As the disease worsens, your phlegm colour will darken from clear and watery to whiter and thicker, eventually yellow: all due to your body producing more inflammation – heat – to burn off the bug. Sometimes, however, if your body cannot produce the heat reaction, you’re left with subdued energy and watery or white runny phlegm. This can become very chronic, and hard for your doctor to identify a disease like pneumonia, which conceivably it could be.
  • Are you wearing enough for your environment?
  • You don’t take enough exercise to warm you up and burn away the cold


woman in pink jacket lying on gray couch

If you always have too much clear and watery mucus, ie chronic:

  • While growing up, you were often cold or wore too little
  • you have recently had an acute, exhausting, illness, exhausting both your yin and yang resources. This clear phlegm may continue until you recover. You should avoid cold foods  and take time to convalesce and recover with rest and sleep.
  • 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 for your metabolism and circulation

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 food, containing sugar or other sweeteners that weaken your Spleen energy
  • Possibly you are eating too much dairy food (= from cows) such as milk, cheese, cream, yogurt, kefir and lassi, which have a ‘cold’ energy
  • 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)


fries on black paper cone

  • 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 (which, from the infection, was probably yellow or green, being 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 over-using them, so read Suppression.) That underlying problem is a lack of reactivity, making you susceptible to further infections.
  • White phlegm also occurs in bronchitis, COPD, reflux from your stomach (probably from Stomach Qi ‘rebelling’). These occur with various syndromes in Chinese medicine.

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 – preferably several times a day!


woman in white tank top running on dirt road during daytime - running creates heat that dries white phlegm colour
Running for Life! Photo by Greg Rosenke
  • keeping warm – not least in bed when asleep – but when exposed to cool environments
  • getting enough good sleep
  • doing deep breathing
  • eating more warming or Hot foods
  • eating less cooling or Cold Foods


All these help to increase your body’s warmth, compensating for the coldness of the food. As your metabolism warms up it will produce less runny white phlegm.

White catarrh, like uncooked egg-white, 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 or dark-yellow? eg yellow mucus or dark-yellow mucus


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’
  • you also get yellow phlegm with bronchitis as your body reacts with inflammation, similarly with pneumonia and less seriously with sinusitis
  • 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. Even so, my body reacted to it with some phlegm!)

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 you have green phlegm? – Green sputum – ‘green mucus’ and ‘dark green mucus’, ‘dark green phlegm’ and ‘thick green mucus’


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


Coughing up green ‘mucus’? 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:

Western-medicine-diagnosed conditions include bronchitis, pneumonia, sinusitis and also cystic fibrosis.

Brown phlegm, sometimes called brown mucus: can be brown-green

As phlegm ages it goes darker. That your phlegm is not yellow, green or red means it is less acute, more chronic. With this brown or brown and green ‘mucus’ (ie phlegm) you have to accept that your body’s reactive powers are diminished. This stuff is older. So, besides whatever syndrome is diagnosed there is almost certainly some yang deficiency, probably being Kidney Yang deficiency and Spleen yang deficiency.

Possible Western-medicine defined diseases for brown phlegm include bronchitis, lung abscess, pneumonia and cystic fibrosis.

Red phlegm colour ie Rust-coloured sputum


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.

In Chinese medicine, it can occur with Heart Blood stasis or Lung Heat for various kinds of Western diagnosed conditions including pneumonia, TB as mentioned, and pulmonary embolism.

Black phlegm

Black phlegm looks alarming!

I once helped my sister move house. I cleared her attic.

When building the house 100 years earlier, the builders had put soot 10cm deep between the joists as insulation to prevent heat loss from the rooms underneath into the roof void.

In the dark, moving stored paraphernalia, I disturbed the soot particles.

I emerged looking like a coal-miner newly up from a deep mine. Some hours later I started coughing and spat out huge quantities of black sputum.

But several days later it had all cleared and my excitement diminished!

What did I learn from this?

Air pollutants darken phlegm colour
Air pollution is bad for your lungs! Photo by Anne Nygård

Air pollutants can cause black phlegm

  • Smoking eg cigarettes
  • Dirt from industrial and chemical processes
  • Unclean air
  • Exposure to Fire and the smoke and soot it produces


Exposure to infection and your body’s reaction over time

  • One diagnoses infections because they come with other symptoms, for example of fever, malaise, tiredness and symptoms of the disease in question. Most such reactions are with Heat.
  • Tuberculosis produces symptoms of heat, darkening phlegm colour, and in time can cause bleeding – red phlegm. This red blood gradually darkens to black as it ages and thickens
  • Fungal infections in the Lungs produce symptoms of Damp, often combined with Heat. Eventually the phlegm darkens from the Heat, becoming blacker.
  • Cancer of the lungs or stomach leads to bleeding from Blood stagnation. As the blood ages it darkens so you find yourself coughing up black stuff.
  • Other infections, such as pneumonia, can lead to Blood stagnation, darkening Blood towards Black.
  • During Heart Blood stagnation, the heart valves may, in effect, be unable to push blood forwards into circulation. Some blood may find its way back to the lungs, causing Lung Blood stagnation. Here it may escape and need to be spat out, by when it will be black. 

What about hard phlegm chunks, coughing up hard mucus, or dark pellets of catarrh?

too many brown cookies can lead to dark chunks of phlegm!
Cookies to Chunks – Photo by Kelly Visel

If there is redness in or round them, probably your lungs are bleeding: see red phlegm, above

Otherwise, the fact they’ve gone hard means they’ve been there for some time, slowly losing moisture and hardening the original phlegm.

Fortunately, your body now has enough strength to cough them up. So they may be from a former illness, almost forgotten, now expelled by your stronger body.

To make sense of them read what is said above about Black phlegm.

(More) Pages to read

Related Articles

photo of person showing silver-colored ring
Causes of disease

Knee Pain

Knee pain has five main causes. It’s certainly worth trying acupuncture before you resort to surgery!

Read More »

3 Responses

    1. Thanks Bruce – yes! Our bodies produce many signs which traditional medicines learned to use to diagnose disease, and to measure improvement from changing our habits and from treatment. Once you get the basic idea, you can often work out what you’re doing wrong. Best wishes Jonathan

  1. Thank you very much Jonathan , this is a lovely depiction with your use of photos and a very positive inspiration to delve deeper. Thank you very much Jonathan 😊

Leave a Reply

Your email address will not be published. Required fields are marked *