Causes and risk factors for increased mucus production

Mucus can tell a good health story.

Excessive mucus is a sign of chronic respiratory disease, acute illness, and some types of chronic obstructive pulmonary disease (COPD). While mucus is good for the body, producing too much mucus can lead to breathing difficulties and infections.

This article explains the causes of excess mucus and how genetics and lifestyle choices can add to the problem.

Common causes

Mucus is often mistaken for saliva, but the two substances are not the same.

Saliva is the fluid produced in your mouth to help you break down and swallow food. The mucus lines the tissue, and its smooth finish traps potential irritants. Mucus contains dead cells and debris from the upper and lower airways, trapping them, along with bacteria, so that everything can be coughed up and cleared from the lungs.

Mucus (also called sputum) is produced by goblet cells and submucosal glands. Overproduction or hypersecretion can occur due to dysfunction of these cells, infection, inflammation, irritation, or debris in the airways.

People with chronic respiratory disease almost always learn to live with increased mucus. It’s a fact of life. They may also have flare-ups and cough up more mucus.

Certain conditions are the main triggers for mucus production:

respiratory infection

Anyone can have a transient respiratory illness that causes increased mucus in the lungs. In fact, acute respiratory infections are one of the most common reasons people seek medical care in the United States.

The common cold is a common cause of viral and bacterial respiratory infections. In some of the most severe cases, the infection can lead to bacterial pneumonia.

The lungs respond to infectious organisms by generating an immune response to eliminate the infection. When you have an infection, mucus production increases to help destroy invading microbes.

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In general, the mucus should decrease to normal levels within a few days of your recovery.

Overview of Pneumonia


Asthma is characterized by episodes of respiratory distress caused by weather changes or substances in the air, such as particulate matter, pollen, and pet dander.

During an asthma attack, you may experience “overproduction” of mucus. Even experts have a hard time defining “too much” mucus or even what “too much mucus” is, since it is assumed that the human body produces about 1 liter of mucus per day.

chronic bronchitis

Chronic bronchitis is a chronic obstructive pulmonary disease associated with excess mucus in the lungs. The main reason is smoking.

The diagnosis of chronic bronchitis is based on coughing most of the week with active mucus production for at least three months (and two years). Other lung diseases, such as tuberculosis, must be excluded.

When bronchitis flares up, the mucus builds up more than usual.

mucus and phlegm

Many people use the words “mucus” and “phlegm” as if they were the same. But there are several differences that separate them:

  • Mucus is a clear fluid that lines the nose, mouth, and throat.
  • Phlegm is a type of mucus produced by the lungs and lower respiratory tract. The presence of phlegm means that the lungs and airways are irritated.
  • Mucus is usually expelled from the nose; phlegm is usually expelled from the lungs (by coughing).

Emphysema and Bronchiectasis

Another chronic obstructive pulmonary disease, emphysema is characterized by increased mucus production, coughing and susceptibility to lung infections.

Bronchiectasis is a condition in which repeated infections cause permanent enlargement of the airways. It often produces thick, foul-smelling mucus.

Pulmonary Edema

With pulmonary edema, a deleterious increase in lung fluid develops. It can cause shortness of breath. In fact, dyspnea can cause people with pulmonary edema to wake up soon after falling asleep and have trouble breathing.

Combined with more mucus than usual, breathing can become more difficult. The mucus is usually foamy in appearance and may be pink in appearance due to the presence of blood.


There are several genetic disorders associated with increased mucus. Some conditions directly affect the lungs, while others damage the muscles involved in breathing, causing increased mucus in the airways:

  • Cystic fibrosis is an inherited disease that affects multiple systems in the body, including the respiratory and digestive systems. Increased mucus is the main feature of this condition.
  • Primary ciliary dyskinesia is an inherited disorder characterized by defects in cilia (tiny hair-like structures). It causes an increase in mucus in the lungs and can lead to breathing difficulties and infections.
  • Neuromuscular diseases like muscular dystrophy and spinal muscular atrophy can also cause excess mucus because they impair muscle function. This, in turn, reduces lung movement as you inhale and exhale, and reduces the strength and ability of your cough. Mucus then builds up in the lower lungs.

Lifestyle Risk Factors

Environmental irritants such as cigarette smoke and pollutants cause goblet cells to produce and secrete mucus, while damaging cilia and airway structures.

Exposure to these irritants, especially if you already have lung disease, greatly increases your risk of excess mucus in your lungs.

Common irritants include:

  • Indoor air particles (dust or pet hair)
  • Indoor or outdoor smoke or workplace emissions
  • outdoor air pollution
  • tobacco smoke


Sometimes, when it comes to excess mucus, there can be multiple factors at play. For example, you may have stable emphysema, but you may develop extra mucus when you are exposed to cigarette smoke. Or, you may have chronic bronchitis with increased mucus when you have the flu.


Anyone who’s ever dealt with a respiratory infection like bronchitis knows that excess mucus can come with territory. Bronchitis is one of several diseases that can trigger this state. The same goes for asthma, pneumonia, and emphysema, as well as genetic and environmental factors. If a discerning healthcare provider can identify and treat the underlying cause, mucus production should return to normal.

VigorTip words

A cough may seem like a “little thing,” but a persistent cough may indicate that you have a medical condition that requires medical attention. So don’t brush it. When your health is at stake, it’s wise to consult with a trusted healthcare provider.

reduce excess mucus in the lungs

Frequently Asked Questions

  • Can allergies cause mucus?

    Yes. Allergies involve the release of histamine and other chemicals that irritate the mucous membranes lining the nose. Irritation can cause excess mucus production.

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  • What can I do to stop mucus reflux?

    Dietary changes are the number one recommendation for relief from laryngopharyngeal reflux or gastroesophageal reflux disease (GERD), both of which increase mucus. Avoid irritating foods, including alcohol, caffeine, carbonated drinks, spicy and fried foods, chocolate, mint, tomatoes or citrus fruits. Eating small, frequent meals can also help.

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  • How do I deal with excess morning mucus from COPD?

    Morning mucus is common in COPD, even when following good practices such as your treatment plan and not smoking. Use a deep cough to clear phlegm, discuss possible adjustments to your medications with your doctor, and meet with a sleep specialist if possible. Getting a good night’s sleep can help relieve some morning symptoms.

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