Yellow To Green Mucus


Mucus is a viscous fluid that lines the walls of moist surfaces in the body such as those found in the lungs, mouth, sinuses, intestines, and stomach. As you might have guessed, they act as a lubricant, but they are also one of the first lines of defence against pathogens. Mucus can also easily be confused with phlegm, but the key difference is that mucus is a thinner secretion from the nose and sinuses, whereas phlegm is secreted from the throat and lungs.1 The colour of your mucus can be a very important indication of your body’s health. So, in this article, we will explore why mucus changes colours, what these colours could mean and what would be some potential treatment options.

Why does mucus change colour? 

If your mucus changes colour it can be a sign of your body’s immune system response and that it is fighting some sort of infection or disease. The colour of the mucus, therefore, dictates how serious the condition is, which is what we will explore in the next section.

Colours of mucus and what this means

There are various colours that mucus can be: Clear, yellow, green, Red/Pink, Brown, or Black. Let’s discuss what these can mean:2

Clear: While this is normal, if you are having the excess passage of clear mucus, this usually means that the body is fighting off an allergy which could be due to dust or other allergens 

Yellow: If you are passing yellow snot, it almost certainly means that your body is fighting off an infection and the yellow colouring is due to the white blood cells travelling to the site of infection to fight off the pathogens  

Green: This indicates a potent infection in the body and signals that a significant number of white blood cells of the immune system are involved in the immune response.

Red/Pink: As you might have guessed, this indicates blood in your snot but it may not be too alarming since this is normal in viral infections and allergies when you have to blow your nose multiple times, or if you have used the nasal sprays multiple times - this causes the nasal passageways to dry out and due to the excess friction, it could cause minor bleeding. 

Which colour of mucus do i need to worry about? 

If you notice continuous bleeding from your nose, then it may be a cause for worry. In addition, black snot might also be a cause for worry. If you smoke, black snot could be a normal occurrence due to the inhalation of chemicals. In addition, if you work in an industrial area with exposure to allergens and irritants, then it is possible that your snot might be black due to your body trying to expel those chemicals. But, a black snot could also mean a serious fungal infection and this should be a cause for worry.2

When do you seek medical attention? 

As a rule of thumb, if you notice continuous bleeding from your nose, continuous red snot or black snot, it would be best to seek advice from your healthcare provider. 

Medication and ways to get rid of mucus at home

There are some medications and some home remedies that you can take to get rid of mucus at home:3,4

  1. Decongestants can be an excellent form of mediation for the removal of excess phlegm. They come in multiple forms be it nasal sprays, drops, tablets, syrups, or flavoured powders. A prominent example is Sudafed
  2. Hypertonic Saline - This is essentially a salt solution of different concentrations (3, 3.5, and 7%). Taken through a nebuliser, it works by adding salt to the airways, which attracts water, having the final effect of thinning the mucus
  3. Mannitol - this is an inhaled powder that makes it easier to cough up mucus. Its mechanism of action is unknown 
  4. Stay away from allergens and irritants
  5. Saline nasal rinses are especially useful in these cases - you can either buy them from the pharmacy or make it at home using half a teaspoon of salt and approximately 550 mL of water
  6. Avoid dry, warm, and humid environments
  7. Drink plenty of water and fluids

It is important to remember that some of the medications listed above can have side effects depending on your specific medical history, so be sure to speak to your healthcare provider before taking any of them  


In summary, mucus is an important component of normal body functioning. Normally, it is clear, but if there is excess production of mucus it usually means the body is fighting off allergies. If your mucus changes colour, it signals an immune response to infection, and depending on the colour you might be able to gauge the severity of the infection. There are several medications and home remedies that you can take to ease the symptoms, but before taking any medications please consult with your physician as these can have side effects. Lastly, if you notice continuous red and especially black snots, get it checked by your healthcare provider as a matter of priority.


  1. Mucus and Phlegm: Barometers of Your Health | Premier Health [Internet]. Available from:
  2. Faley K. What the color of your snot means [Internet]. OSF HealthCare Blog. 2022 [cited 2022 Oct 29]. Available from:‌
  3. Mucus Thinners | Cystic Fibrosis Foundation [Internet]. Available from:
  4. Catarrh [Internet]. 2017. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Punyaslok Mishra Mishra

MB BCh BAO - Queen's University Belfast, Northern Ireland

Punyaslok is an emerging medical professional from Queen's University Belfast with a specialization in Medicine. He has showcased leadership as the President of the Asian Medical Students’ Association in Northern Ireland since August 2022. Besides, he contributes as a Peer Mentor and has recently undertaken a vital role as a Medical Writer Intern at Klarity, where he pens insightful articles for a health library, discussing topics from angina to the enzymes in papaya. Notably, Punyaslok's research on the potential of Mesenchymal Stem Cells in treating Anthracycline Induced Cardiomyopathy is affiliated with Queen's University, signifying his deep interest in advancing therapeutic measures in the medical realm.

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