A congested chest

Chest Congestion Causes

When we become ill or our respiratory system becomes irritated, chest mucus or phlegm is produced in larger amounts than normal in order to fight off foreign bodies. After the phlegm has served its purpose, it is expelled from the body by coughing. So, next time you are coughing up mucus, know that even though it is unpleasant, it is a sign that your body is fighting off infection or trying to clear your lungs of harmful irritants. Here are some of the most common causes of chest congestion.


Allergies are one of the biggest contributors to the development of chest mucus. The most common allergen is ragweed pollen, which is responsible for hay fever. While the mucus membranes in your nose and throat try to trap and sweep away allergens, your body is producing excessive mucus, which can lead to congestion.

Viral or Bacterial Infection

One of the most common causes of chest congestion is common illnesses such as the cold or the flu. Since your body is being attacked by a virus or a bacterial agent, it produces a lot more mucus than normal, which can begin to collect in your lungs and nasal cavities. It is also common to cough up phlegm if you are suffering from a viral or bacterial infection.

Post Nasal Drip

This condition is classified as the backward flow of mucus draining from the sinus cavities down the throat. Because of the constant dripping, this can lead to congestion and irritation. There are many causes of post nasal drip, including dairy products, dry climates, irritants, smoking, colds, flu, and pregnancy. This condition can also be a symptom of gastroesophageal acid reflux, which is a swallowing dysfunction that causes the gastric contents in your stomach to come back into your esophagus or throat.


Bronchitis is a bacterial or viral infection of the bronchial tubes, which are the primary airways to the lungs. There are different types of bronchitis that affect different parts of your lungs, but all types of bronchitis can lead to the production of large amounts of mucus and phlegm. This excess mucus will fill up some areas of your lungs, which can cause problems with breathing and cause chest congestion.


Pneumonia in the lungs can develop from a bacterial, viral, parasitic, or fungal infection. It can also be caused by autoimmune reactions. Pneumonia is a potentially life-threatening condition that can lead to symptoms such as fever, fatigue, and congestion of the chest and sinus cavity, which can lead to difficulties breathing.


Tuberculosis is an infection that is caused by a bacterium called mycobacterium tuberculosis. Though it can affect various different parts of your body, when it attacks the lungs, it causes symptoms such as severe coughing, difficulty breathing, and chest congestion. If left untreated, this disease can be fatal.

Congestive Heart Failure

Congestive heart failure occurs when your heart is unable to pump blood effectively throughout your body. One of the main symptoms of this disease is lung congestion, since fluid accumulates in the lungs. 

Last Updated: December 16, 2016