I Am Coughing Up Green Mucus – Why?

Despite the somewhat comical name, phlegm provides a useful function.k It keeps your nasal tissues moist and clean of bacteria and viruses.

Normally, phlegm is clear and produced in small quantities. However, when an infection flares up, your lungs start producing more of it and it may change color.

The color, amount, and texture of the mucus are among the indicators of how your body is faring. Usually, at the onset of an infection, the mucus starts out clear or white. It can change color over time, depending on the severity and the type of disease.

The change in color comes from the dead white blood cells that your body is using to fight the disease off. Yellow, green, brown, white, black, red, and pink hues mean different things and are associated with different diseases.

Doctors use the color and quantity of phlegm to assist with a diagnosis. With the start of a cold, phlegm can go from clear to yellow to green(ish).  Brown indicates there may be blood in your phlegm. Black, on the other hand, indicates a fungal infection.

Coughing up green mucus? Why? Read on for more info on the symptom and how it relates to pulmonary and systemic diseases.


Sinusitis (also referred to as rhinosinusitis) is an infection of the sinuses. It manifests as swelling, inflammation, and infection of the nasal cavities. Coughing with mucus, sinus pains, nasal congestion with discharge, sinus headaches, sore throat, and hoarse voice usually accompany sinusitis.

The causes of sinusitis can be grouped under viral (which accounts for the vast majority of sinusitis cases), bacterial, and fungal. The onset can either be acute or chronic.

  • Acute sinusitis. Acute sinusitis lasts up to four weeks, according to the American Academy of Otolaryngology. It often appears together with the common cold or other diseases of the respiratory tract. It shares many common symptoms with the chronic variety, though it is less severe and dangerous.
  • Chronic sinusitis. Chronic sinusitis lasts longer than 12 weeks or reappears frequently. It is characterized by facial pain, congestion, nasal discharge, colored mucus, and other typical sinusitis symptoms.


Sometimes, green phlegm can mean that you have bronchitis. Bronchitis is an inflammation of the bronchial tubes. Most of the times, it starts out as a viral infection that progresses into something bacterial. Dry cough is usually the first noticeable symptom, with wheezing, coughing up mucus, and chest discomfort completing the rest of the primary symptoms.

The appearance of green (sometimes yellow) mucus means that the disease might be progressing from the viral to the bacterial stage and that your immune system is fighting hard to defeat the infection. There are two main types of bronchitis – acute and chronic. Here’s a word or two about each of them.

  • Acute bronchitis. Acute bronchitis is mostly caused by viral infections. Air pollution and bacteria such as Bordetella pertussis and Mycoplasma pneumoniae are the other major causes. Commonly, acute bronchitis lasts up to three weeks and can be treated with paracetamol/acetaminophen and NSAIDs. It is crucial to get plenty of rest while you’re recovering from an episode of acute bronchitis. If left untreated, acute bronchitis can be deadly.
  • Chronic bronchitis. To qualify as chronic, bronchitis must involve productive coughing for at least three months out of a year and lasts for at least two years. Like the acute variant, chronic bronchitis is potentially lethal if left unchecked. Chronic bronchitis often happens in conjunction with other obstructive diseases, such as COPD (chronic obstructive pulmonary disease). Vaccinations, rehabilitation, quitting smoking, and inhaled steroids and bronchodilators are among the common therapy methods. Lung transplantation and long-term oxygen therapy may be considered in severe cases.


Along with bronchitis, pneumonia is the most common pulmonary disease. It is a lung infection that causes inflammation of the alveoli (air sacs). In a pneumonia patient, the alveoli fill up with fluid or pus, making it hard to breathe. The symptoms are coughing up phlegm, fever, shortness of breath, sweating, chest pain, and chills.

As with bronchitis, the change in phlegm (mucus) color from white to yellow and green means that the disease is progressing and that you should visit a doctor. The main types of pneumonia are viral, bacterial, fungal, and mycoplasma pneumonia.

  • Viral pneumonia. Coronaviruses, rhinoviruses, respiratory syncytial virus, influenza virus, parainfluenza virus, and adenovirus are the most common viruses that cause viral pneumonia. This type mostly affects kids and older people. It is less dangerous and severe than bacterial pneumonia. Also, it doesn’t last as long.
  • Bacterial pneumonia. This type is most commonly caused by Streptococcus pneumoniae (around 50% of all community-acquired pneumonia cases). The other common bacteria are Chlamydophila pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Moraxella catarrhalis. Legionella pneumophila is a bacterium that causes Legionnaires disease, a potentially deadly type of walking pneumonia.
  • Fungal pneumonia. Fungi found in bird droppings and soil can also cause pneumonia. This type usually affects people who already suffer from chronic diseases or have compromised immune systems. It is worth mentioning that Pneumocystis jirovecii pneumonia (commonly known as PCP) can be one of the first signs that the infected individual has AIDS.
  • Mycoplasma pneumonia. This type is most commonly found in young adults and older children. It is a mild form of pneumonia, caused by mycoplasmas. Mycoplasmas are organisms that share traits with both viruses and bacteria.

Cystic Fibrosis

Unlike sinusitis, pneumonia, and bronchitis, cystic fibrosis is not caused by a pathogen. Instead, it is caused by a mutation or damage in the CFTR (cystic fibrosis transmembrane conductance regular) gene.

This gene is in charge of the movement of water and salt throughout the body and its damage or mutation can cause the mucus in your body to turn stickier and thicker than normal. It can also spur an overproduction of mucus.

Cystic Fibrosis usually attacks the lungs, liver, pancreas, and other glandular organs. Respiratory problems associated with cystic fibrosis include shortness of breath, congested sinuses, continuous cough accompanied by thick (often green) mucus, wheezing, and congested nose. Foul-smelling stools, swellings in the abdomen region, constipation, poor appetite, nausea, slow growth, and low weight in children are among the digestive symptoms of cystic fibrosis.

In order to develop cystic fibrosis, a child must inherit the defective gene from both parents. If a child inherits the damaged gene from only one parent, they won’t develop the disease. Instead, they might pass it on to their children.

Antibiotics, NSAIDs, mucus-thinning medications, and bronchodilators are used in treatment. In severe cases, bowel surgery or lung transplants might be needed. If the disease interferes with nutrient absorption, a feeding tube might be inserted into the stomach to supply the missing nutrients.

Final Words

Coughing up green mucus? Why? If it appears on its own and goes away within several days, green mucus is nothing to worry about. That being said, if you notice symptoms of the described pulmonary diseases, such as pneumonia, sinusitis, or bronchitis, you should go see a doctor.

In case the mucus is followed by a combination of pulmonary and digestive problems, you might have cystic fibrosis. If that’s the case, call your doctor as soon as possible.