Irritation of the airways by infections, inflammation, inherited disorders or structural abnormalities can cause increased mucus production and coughing up phlegm. Hair-like projections on the cells, lining the airways, move mucus up and out of the lungs. Heavy mucus production triggers the cough which assist in the expulsion of the excess mucus.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.


Pneumonia is a viral, bacterial or fungal infection of the air sacs and supportive tissues of the lungs. The infecting germs along with the immune system response to the infection cause airway inflammation with an associated increase in phlegm production. The phlegm, also known as sputum, is often thick and opaque, frequently with a yellow or green coloration. Other symptoms of pneumonia include high fever, shaking chills and chest pain, precipitated by inspiration or coughing. The Centers for Disease Control and Prevention reports 1.1 million Americans were hospitalized in 2010 with pneumonia 36.

Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease, or COPD, is a persistent, progressive lung condition most often caused by smoking 6. COPD includes chronic obstructive bronchitis and emphysema 6. Chronic irritation and inflammation of the airways associated with COPD causes markedly increased sputum production and persistent cough. As of 2015, CDC reports that 15 million Americans have been diagnosed with COPD. However, many more people who have not yet been diagnoses may have the illness.

Cystic Fibrosis

Cystic fibrosis is an inherited disorder that causes abnormally thick, sticky mucus 5. Chronic cough is a characteristic symptom of cystic fibrosis as the lungs work to clear the abnormally thick mucus from the airways 5. The sputum coughed up is typically gel-like in consistency and usually green or yellow in coloration. The Cystic Fibrosis Foundation reports approximately 30,000 Americans have been diagnosed with cystic fibrosis 5.


Bronchiectasis is a condition in which damage and dilation of the larger airways -- known as bronchi -- occurs due to chronic infection and inflammation. This condition may be caused by cystic fibrosis, immune deficiency disorders, rheumatoid arthritis, Sjögren's syndrome, tuberculosis and fungal infections of the lung 5.cause:

  • This condition may be caused by cystic fibrosis
  • immune deficiency disorders
  • rheumatoid arthritis
  • Sjögren's syndrome
  • tuberculosis
  • fungal infections of the lung 5

A characteristic symptom of bronchiectasis is coughing up large quantities of malodorous sputum. Coughing up blood also often occurs with this condition.

Pulmonary Edema

Pulmonary edema is usually a complication of heart failure. With heart failure, the heart is too weak to pump a normal volume of blood into the circulation. Like a vascular traffic jam, blood backs up in the lungs causing fluid leakage into the air sacs. This leads to marked shortness of breath and coughing up foamy sputum. The sputum may be streaked with blood. Pulmonary edema is a potentially life-threatening condition requiring immediate medical intervention.

Seek Medication Attention

See your doctor if you are coughing up phlegm so you can be accurately diagnosed and treated. Seek immediate medical care if you experience difficulty breathing, shortness of breath or chest pain.