Coughing Up Mucus- What Does it Mean vector

Coughing Up Mucus: What Does it Mean? (2024)

by | Updated: May 30, 2024

Coughing up mucus is a common physiological phenomenon, often a protective reflex of the human body intended to clear the respiratory passages of irritants, microbes, or obstructions.

Mucus, or phlegm, is typically produced by the mucous membranes in the respiratory system, playing a crucial role in maintaining respiratory health by trapping foreign particles and microbes.

When the respiratory system is under threat, mucus production can increase, leading to symptoms such as coughing and congestion.

The color, texture, and amount of mucus can provide valuable insights into underlying health conditions, ranging from common colds and allergies to more serious conditions such as bacterial infections and chronic respiratory diseases.

What Does it Mean When You Cough Up Mucus?

Coughing up mucus, or phlegm, often means your body is fighting an irritant, infection, or disease in the respiratory system. The mucus traps foreign particles and microbes, and expelling it helps clear the airways. The color and texture of the mucus can indicate whether it’s due to a cold, an allergy, an infection, or a chronic condition.

man coughing up mucus vector illustration

What is Mucus?

Mucus is a viscous, slippery substance produced by mucous membranes found throughout the body, including the respiratory, digestive, and reproductive tracts.

Composed of water, glycoproteins, lipids, and electrolytes, mucus serves several crucial functions, primarily serving as a protective barrier and lubricant.

It traps dust, bacteria, viruses, and other foreign particles, preventing them from entering the body and causing infections.

Additionally, mucus hydrates the surface of the membranes and facilitates the removal of these trapped particles through processes like coughing, sneezing, and swallowing.

Mucus Composition

Mucus is a complex, viscous fluid secreted by goblet cells and mucous glands. Its composition includes the following components:

  • Water: The primary component of mucus, water makes up about 95% of its composition, providing the necessary hydration for the proper functioning of mucus.
  • Mucins: These are large glycoproteins that give mucus its gel-like properties. Mucins interact with water to give mucus its viscous and elastic characteristics.
  • Ions: Including sodium and chloride, ions help maintain the proper electrolyte balance and pH within the mucus, crucial for its antimicrobial activity.
  • Lipids: These are fatty substances, including phospholipids and cholesterol, that contribute to the protective barrier function of mucus.
  • Enzymes: Such as lysozyme, enzymes in mucus have antimicrobial properties, breaking down the cell walls of bacteria and aiding in the protection against infections.
  • Antibodies: Immunoglobulins, particularly IgA, play a critical role in immune defense, neutralizing pathogens that enter the respiratory and gastrointestinal tracts.
  • Cells: Sometimes, mucus contains cells shed from the mucous membranes or immune cells that are part of the body’s defense mechanisms, like white blood cells.
  • Salts: These help to maintain the osmotic balance within the mucus and participate in hydration.
  • DNA: Coming from the cells in the mucus or microbes, DNA is often found in mucus, especially during infections or inflammation.

Note: This combination of components enables mucus to trap foreign particles, such as dust, microbes, and pollutants, and keep the underlying tissues moist and protected.

Types of Mucus

Mucus can vary in composition, texture, and color, depending on its location in the body and the presence of any underlying conditions.

Here are several types of mucus based on these variations:

1. Clear Mucus

Clear mucus is normal and is usually a sign of a well-hydrated and healthy respiratory tract. It acts as a lubricant and traps dust, microbes, and foreign particles, preventing them from reaching the lungs.

It’s typically thin and watery and is produced by the nasal and bronchial mucous membranes.

2. Frothy White Mucus

Frothy white mucus can be indicative of air mixing with the mucus, possibly due to conditions like chronic obstructive pulmonary disease (COPD) or asthma.

It may also appear in cases of gastroesophageal reflux disease (GERD), where stomach acid irritates the throat, causing the mucus to become white and frothy.

3. Thick Mucus

Thick mucus is often associated with dehydration, lower temperatures, or respiratory infections.

It is more viscous and can obstruct the airways, causing discomfort and difficulty breathing. Hydration, humidification, and expectorants can help in thinning the mucus, aiding its expulsion.

4. Black or Gray Mucus

Black or gray mucus usually signifies the presence of inhaled pollutants or smoke. It can be seen in smokers or individuals exposed to high levels of air pollution, dust, or dirt.

Persistent black or gray mucus, especially in non-smokers, should prompt medical evaluation to rule out fungal infections or other serious conditions.

5. Yellow or Green Mucus

Yellow or green mucus is usually indicative of a bacterial infection. The coloration is primarily due to the presence of white blood cells, notably neutrophils, responding to infection.

While it can be a sign of a resolving infection, persistent yellow or green mucus, especially when accompanied by other symptoms, may necessitate medical attention and possibly antibiotic treatment.

6. Pink or Red Mucus

Pink or red mucus typically signifies the presence of blood, indicating possible irritation or damage to the blood vessels in the mucous membranes.

This can result from a variety of conditions, including trauma, infection, or inflammation, such as bronchitis or sinusitis.

Persistent or recurrent presence of pink or red mucus should prompt immediate medical consultation.

7. Brown Mucus

Brown mucus can be due to the presence of tar, resins, or dirt, typically seen in smokers or those exposed to environmental pollutants.

It can also occur when old blood or dried blood mixes with mucus, giving it a brownish appearance.

Like black or gray mucus, persistent brown mucus necessitates a medical evaluation to exclude underlying respiratory conditions.

8. Phlegm

Phlegm is a type of mucus produced in the lower airways, particularly when there is inflammation or infection in the lungs and bronchi.

It is often thicker and more viscous than nasal mucus and may be expelled by coughing. Phlegm may appear in different colors, each signaling varying underlying conditions and should be evaluated if persistent.

9. Sputum

Sputum is mucus that is expelled from the lower airways through coughing.

It can contain mucus, cellular debris, microbial organisms, and inflammatory cells, and its color and consistency can help diagnose various respiratory conditions.

Sputum examination, including culture and sensitivity, can be crucial in identifying infective organisms and determining the appropriate treatment.

10. Mucus with Bubbles

Mucus with bubbles often indicates the presence of air within the mucus, potentially due to conditions such as bronchitis or asthma, where airway obstruction occurs.

The bubbles might also suggest an increased effort to breathe, causing air to mix with the mucus. While it may not always signify a severe condition, persisting symptoms warrant medical assessment.

11. Pink Frothy Mucus

Pink frothy mucus is often a mixture of air, liquid, and possibly blood, usually indicating the presence of a severe condition like pulmonary edema.

This type of mucus is typically seen in individuals experiencing acute respiratory distress or heart failure and warrants immediate medical attention, as it can signify a critical compromise in lung function.

12. Nasal Mucus

Nasal mucus, produced by the goblet cells in the nasal passages, serves as a protective barrier and a means to trap dust, microbes, and allergens, preventing them from entering the lungs.

This mucus type is usually clear and thin but can change in color and consistency in response to infections, allergies, or irritants.

13. Bronchial Mucus

Bronchial mucus is secreted within the bronchial tubes and acts as a defensive mechanism to trap and expel foreign particles and pathogens from the lower respiratory tract.

When the bronchi are irritated or infected, the mucus can become thicker, change in color, and increase in quantity, potentially causing coughing and breathing difficulties.

Persistent or unusual changes in bronchial mucus should be evaluated by a healthcare professional.

14. Cervical Mucus

Cervical mucus is produced by the cervix and plays a crucial role in the female reproductive system. It changes in consistency and amount during the menstrual cycle, acting as a barrier or facilitator for sperm migration.

Its observation can aid in fertility awareness as it becomes clear and stretchy around ovulation, indicative of a fertile window.

15. Gastric Mucus

Gastric mucus is secreted by the mucous membranes of the stomach. It serves as a protective barrier, preventing the stomach lining from the corrosive effects of gastric acid.

It is crucial for maintaining stomach health, and alterations in its production can lead to conditions like gastritis or ulcers.

16. Intestinal Mucus

Intestinal mucus is produced by goblet cells in the intestines and plays a vital role in protecting the intestinal lining from digestive enzymes and harmful bacteria.

It also facilitates the smooth passage of fecal matter.

Disruption in its normal composition or amount can be associated with various gastrointestinal conditions like inflammatory bowel disease.

17. Ocular Mucus

Ocular mucus, or rheum, is secreted by the conjunctiva in the eye. It serves to lubricate the eye surface and trap debris, protecting the eye.

Its overproduction or changes in consistency could indicate eye conditions such as conjunctivitis or dry eye syndrome and may require medical attention.

18. Sublingual Mucus

Sublingual mucus is produced by the sublingual glands located underneath the tongue. It aids in the lubrication and initiation of the digestive process by mixing with saliva, assisting in swallowing, and protecting the oral cavity’s soft tissues.

Changes in its production or consistency could be indicative of dehydration, oral health conditions, or salivary gland disorders.

19. Earwax

Earwax, or cerumen, is a type of mucus produced by the ceruminous glands in the ear canal.

It protects the ear by trapping dust, bacteria, and other particles, preventing them from reaching the eardrum.

20. Vaginal Mucus

Similar to cervical mucus, vaginal mucus is produced by the glands in the vaginal wall and cervix.

It provides lubrication and a protective environment, and its characteristics can change according to hormonal levels, especially during the menstrual cycle.

21. Sinus Mucus

While nasal mucus and sinus mucus are often considered together, the mucus produced by the lining of the sinuses specifically helps in maintaining the health of the sinus cavities by trapping inhaled particles.

Therefore, it may be worth distinguishing in some contexts, especially when discussing sinus infections.

Note: Each type of mucus has a unique composition that is suited to its environment and function. Additionally, the properties of mucus can change under different physiological and pathological conditions, such as infections or allergies.

How to Stop Coughing Up Mucus

Stopping the production of excess mucus and subsequent coughing involves addressing the underlying cause, and general measures include:

  • Stay Hydrated: Drinking plenty of fluids helps in thinning the mucus, making it easier to expel and reducing cough.
  • Use Expectorants: Over-the-counter expectorants like guaifenesin can aid in loosening mucus.
  • Humidifier or Steam Inhalation: Adding moisture to the air or breathing in steam helps in loosening mucus.
  • Avoid Irritants: Steering clear of tobacco smoke and other irritants can reduce mucus production.
  • Take Antihistamines: If allergies are causing excess mucus, antihistamines can help reduce production.
  • Treat Infections: If a bacterial infection is the cause, antibiotics may be necessary. For viral infections, rest, and hydration are key.
  • Avoid Dairy Products: They can increase mucus production in some people.
  • Use Honey and Lemon: A mixture of honey and lemon in hot water can soothe the throat and relieve congestion.

Note: Always consult a healthcare provider for an accurate diagnosis and treatment plan, especially if symptoms persist or worsen.

FAQs About Coughing Up Mucus

What is the Difference Between Mucus, Phlegm, and Sputum?

  • Mucus: A protective, gel-like secretion produced by mucous membranes throughout the body.
  • Phlegm: A type of mucus produced in the lower airways in response to inflammation or infection of the lungs and bronchi.
  • Sputum: Mucus that has been expelled from the lower airways by coughing and may contain cells, bacteria, or other debris.

How Can I Get Mucus Out of My Lungs?

Mucus can be expelled from the lungs by staying hydrated to thin the mucus, using expectorants like guaifenesin to loosen mucus, practicing breathing exercises or airway clearance techniques.

You may also consider inhaling steam or using a humidifier to moisten the airways, and avoiding irritants like tobacco smoke that can increase mucus production.

What Causes Coughing Up Clear Phlegm with Bubbles?

Coughing up clear phlegm with bubbles is typically a normal process where the mucus is mixed with air, usually indicating a non-infectious cause such as allergies or irritation.

The bubbles can be due to the air being trapped in the phlegm when coughed up.

However, if experiencing persistent symptoms or other accompanying symptoms like shortness of breath or chest pain, it’s essential to seek medical advice to rule out any underlying respiratory conditions.

Related: Coughing Up Phlegm but Not Sick: An Overview

What is Bronchitis?

Bronchitis is an inflammation of the bronchial tubes, the airways that carry air to the lungs. It can be either acute or chronic.

Acute bronchitis is usually caused by viruses and may be accompanied by symptoms like cough, mucus production, fatigue, and mild fever.

Chronic bronchitis, a form of chronic obstructive pulmonary disease (COPD), is a long-term condition often caused by prolonged exposure to irritants like tobacco smoke.

What Does it Mean to Have Blood in My Mucus When Coughing?

Having blood in mucus when coughing could be indicative of a respiratory tract infection, prolonged coughing, or irritation causing damage to the blood vessels in the airways.

While small amounts of blood may not be alarming, the consistent presence of blood in mucus necessitates medical evaluation to rule out more serious conditions like tuberculosis or lung cancer.

Does Coughing Up Mucus Mean I’m Getting Better?

Coughing up mucus can be a positive sign in respiratory infections as it helps clear pathogens from the respiratory system.

However, if mucus is persistent, changes color, or is accompanied by other symptoms like fever or breathlessness, it may indicate a worsening condition or secondary infection.

Note: Always monitor symptoms closely and seek medical advice if needed.

Can COVID-19 Make You Cough Up Mucus?

Yes, COVID-19 can lead to respiratory symptoms, including coughing up mucus, as it primarily affects the respiratory system.

However, symptoms vary widely, and many individuals experience dry cough, fever, fatigue, and loss of taste or smell.

Severe cases may lead to pneumonia and respiratory failure. Any suspected symptoms of COVID-19 should prompt immediate testing and isolation.

Is It Good to Spit Out Mucus When Sick?

Yes, it is generally good to spit out mucus when sick, as it can help remove irritants, pathogens, or debris from the respiratory tract.

Swallowing mucus is not harmful as the stomach acid neutralizes pathogens, but expelling mucus can aid in recovery by clearing the airways and reducing irritation and coughing.

Can Coughing Up Mucus Make Your Throat Sore?

Yes, frequent coughing can irritate the throat lining and lead to soreness. Coughing up mucus, especially if it is thick or in large quantities, can further irritate the throat.

Keeping the throat moist with lozenges, gargling with salt water, and staying hydrated can help soothe a sore throat induced by coughing up mucus.

Can Coughing Up Mucus Be a Sign of Pregnancy?

Coughing up mucus is not typically a sign of pregnancy. It is usually related to respiratory or allergic conditions.

However, during pregnancy, hormonal changes can lead to an increase in mucus production, and a weakened immune system can make pregnant individuals more susceptible to respiratory infections.

Any persistent or concerning symptoms should be discussed with a healthcare provider during pregnancy.

Does Coughing Up Mucus Always Mean Infection?

No, coughing up mucus does not always indicate an infection. The body naturally produces mucus to trap foreign particles, and coughing helps to clear the airways.

However, changes in mucus color, texture, or quantity, or the presence of additional symptoms like fever or body aches, could be indicative of an infection or another medical condition that might require attention and possibly treatment.

Final Thoughts

The act of coughing up mucus is the body’s innate response to protect the respiratory system from irritants, infections, and diseases.

The nature of the mucus coughed up serves as an important indicator of the individual’s respiratory health and can signify the presence of varying underlying conditions, from benign to severe.

Understanding the reasons behind increased mucus production and paying attention to the characteristics of the expelled mucus can aid in early detection and appropriate management of respiratory conditions, contributing to overall well-being and preventing complications.

The knowledge of when to seek medical advice is crucial to ensuring optimal respiratory health and responding adequately to the signals our bodies send us.

John Landry, BS, RRT

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.


  • Farzan S. Cough and Sputum Production. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 38.
  • McShane A, Bath J, Jaramillo AM, Ridley C, Walsh AA, Evans CM, Thornton DJ, Ribbeck K. Mucus. Curr Biol. 2021 Aug 9
  • “Long COVID: Cough.” Long-term Effects of COVID-19.

Recommended Reading