The nose, mouth, and throat are lined with a transparent fluid called mucus. A form of mucus, known as phlegm, is produced by the lungs and the lower respiratory tract and acts as an indicator of inflammation of the airways. According to the American Lung Association, it is a common sign of chronic lung conditions.
In healthy airways, oxygenated air flows smoothly through tubes with the assistance of microscopic hairs called cilia that line the airways.1 As irritants are trapped in your airways and helped to be expelled by coughing, mucus plays a crucial part in your lung's immune response. 1You are more resistant to infection as a result.1
Common causes of phlegm
Several medical problems, including the following, might cause an excessive amount of phlegm to be produced:
- Viral infections such as the common cold
- Bacterial infections
- Allergies such as hay fever
- Acid reflux
- Acute and chronic bronchitis2
- Chronic obstructive pulmonary disease (COPD)2
- Cystic fibrosis
- Whooping cough
- Nontuberculous mycobacteria lung disease
- Sinus infection
- COVID-19 (coronavirus)
Additional lifestyle and environmental factors that can cause excessive mucus production include:
- Chronic persistent pollutant4
- Mediation such as aspirin-containing products and beta blockers
- Particular fluids can lead to fluid loss such as alcohol, coffee and tea
Signs and symptoms
Coughing usually occurs to expel phlegm, which is frequently accompanied by symptoms including runny nose, sore throat, and nasal congestion.
Phlegm typically appears to be clear, yellow or green, but in extreme cases, it may be pink, brown or contain blood. The phlegm may sometimes be unusually thick or foamy, and you may find it challenging to cough out enough mucus to open your airways, causing breathing difficulties.
Types of phlegm
Clear phlegm is normal and is made of water, salt and other cells. An increase in clear phlegm may indicate that a virus or other irritant is being eliminated by your body. Allergic rhinitis (commonly known as hay fever or nasal allergy) is a common cause of clear phlegm.6
Green or yellow phlegm is probably caused by an infection. The colour of the phlegm alone cannot actually tell you what kind of infection you have e.g. bacterial or viral. If any of your other symptoms worsen, always seek medical attention.
A phlegm that is red or pink may indicate a serious warning sign. Heavy coughing can damage blood vessels in the lungs, which can result in bleeding and red phlegm. Red or pink phlegm, however, can sometimes be brought on by more serious illnesses. If there is blood in your phlegm, it is important to see a doctor as soon as possible as this could be a sign of a serious chronic lung condition which needs to be treated.
Due to the presence of blood and the severe chronic inflammation that results from a chronic lung condition, the phlegm can be brown. The bacteria inside the lungs gradually alter the texture and appearance of phlegm. If you have a persistent lung condition, it might be normal for you to notice that you have brown phlegm.
Is there such a thing as “good phlegm”?
A mucus that is thin and clear is healthy and typical. Phlegm that is white, and thicker and causes feelings of congestion could be early signs of an infection.
Effects of phlegm in our body
Although phlegm by itself is not harmful, it can obstruct the airways when it is present in significant amounts.
Risks of having phlegm
Mucus is used to remove pathogens from the body. Although this is beneficial to our bodies, if we produce too much mucus it can lead to infections and difficulties in breathing.
Phlegm may accumulate in your throat and lungs, blocking your airways and, in severe conditions, making it difficult to breathe or swallow.
Treatment and prevention
- Drinking water - This can help you to stay hydrated and improve the congestion in your body by allowing the phlegm to move easily
- Nasal saline spray - These can help relieve congestion
- Gargling with salt water - salt water is also beneficial if you have a sore throat as it can relief the irritant symptoms of it as well as allowing phlegm to move more easily by making it loose
- Humidifier or steam - Congested mucus may better drain with the use of steam and humidifiers7
- Postural drainage - Postural drainage is a method that entails lying or sitting in specific positions to allow gravity to remove secretions from your airways.
- Controlled coughing - This helps to move and loosen mucus. You can find exercises here.
- Mucolytics - Mucolytics are medications that help patients with COPD, cystic fibrosis, and bronchiectasis manage mucus hypersecretion and related effects, such as recurring infections.8
- Expectorants - A cough suppressant that works to help you clear phlegm from your airways.9
- Chest Physiotherapy (CPT) - Research has shown that a form of physiotherapy known as chest physical therapy aids in the removal of mucus and other airway secretions to improve the passage of air into the lungs.10
- Quit smoking - Research has shown that tobacco smoke causes mucus overproduction so quitting cigarettes could help to decrease the amount of mucus in your body.5
- Vaccinations - Getting your vaccinations for diseases such as influenza (flu) and COVID-19 could help prevent the symptoms of phlegm and congestion
When to contact a doctor
Normal mucus production should resume once a physician can identify and address the underlying issue. Therefore, it is important to see a doctor if your phlegm production is abnormal so you can receive the correct treatment for better health.
A cough or phlegm might seem minor and normal but a persistent cough or phlegm with blood could be a sign that you have a serious condition that needs medical attention and should not be ignored. When your health is at risk, the best step would to be consult a doctor.
- NT Contributor. The physiology of mucus and sputum production in the respiratory system | Nursing Times [Internet]. Nursing Times. 2003 [cited 2022 Oct 3]. Available from: https://www.nursingtimes.net/clinical-archive/respiratory-clinical-archive/the-physiology-of-mucus-and-sputum-production-in-the-respiratory-system-10-06-2003/
- Poole P, Chong J, Cates CJ. Mucolytic agents versus placebo for chronic bronchitis or chronic obstructive pulmonary disease. Cochrane Database of Systematic Reviews [Internet]. 2015 Jul 29 [cited 2022 Oct 3]; Available from: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD001287.pub5/full
- Dunican EM, Elicker BM, Gierada DS, Nagle SK, Schiebler ML, Newell JD, et al. Mucus plugs in patients with asthma linked to eosinophilia and airflow obstruction. Journal of Clinical Investigation [Internet]. 2018 Feb 5 [cited 2022 Oct 3];128(3):997–1009. Available from: https://www.jci.org/articles/view/95693
- Marczynski M, Lieleg O. Forgotten but not gone: Particulate matter as contaminations of mucosal systems. Biophysics Reviews [Internet]. 2021 Sep [cited 2022 Oct 6];2(3):031302. Available from: https://aip.scitation.org/doi/pdf/10.1063/5.0054075
- Strzelak A, Ratajczak A, Adamiec A, Feleszko W. Tobacco Smoke Induces and Alters Immune Responses in the Lung Triggering Inflammation, Allergy, Asthma and Other Lung Diseases: A Mechanistic Review. International Journal of Environmental Research and Public Health [Internet]. 2018 May 21 [cited 2022 Oct 3];15(5):1033. Available from: https://www.mdpi.com/1660-4601/15/5/1033
- Shweta Akhouri, House SA. Allergic Rhinitis [Internet]. Nih.gov. StatPearls Publishing; 2022 [cited 2022 Oct 6]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538186/
- Singh M, Singh M, Jaiswal N, Chauhan A. Heated, humidified air for the common cold. Cochrane Database of Systematic Reviews [Internet]. 2017 Aug 29 [cited 2022 Oct 6];2017(8). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6483632/
- Gupta R, Wadhwa R. Mucolytic Medications [Internet]. Nih.gov. StatPearls Publishing; 2022 [cited 2022 Oct 4]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK559163/
- Rubin BK. The pharmacologic approach to airway clearance: Mucoactive agents. Paediatric Respiratory Reviews [Internet]. 2006 Jan [cited 2022 Oct 6];7:S215–9. Available from: https://www.sciencedirect.com/science/article/abs/pii/S1526054206002454?via%3Dihub
- Selvia David Richard, Heri Ariyanto, Setiawan H. Implementation of Evidence-Based Nursing for Expelling Sputum in Tuberculosis Patients with Chest Physiotherapy and Effective Coughing Exercises: A Case Study. International Journal of Nursing and Health Services (IJNHS) [Internet]. 2022 [cited 2022 Oct 4];5(3):259–66. Available from: https://www.ijnhs.net/index.php/ijnhs/article/view/596