Healthy phlegm is usually clear and runny, but many different health conditions can change the consistency or color.

Phlegm, also called sputum, is mucus produced by your lungs that helps protect your airways against germs and irritants.

White, yellow, or green phlegm can be a symptom of an infection in your respiratory tract. Conditions such as infections, allergies, or dehydration can cause your phlegm to thicken and clump.

Most conditions that change the color or consistency of your mucus aren’t serious, but some may need medical attention.

Read on to learn some of the reasons you may be coughing up white or clear balls of phlegm.

Many different conditions can lead to changes in your mucus. A doctor or healthcare professional can run specific tests to help you figure out what’s causing your symptoms. Here are a few of the most likely reasons your phlegm may appear solid or round.

Tonsil stones

Tonsil stones are hardened masses of food debris that get caught in the back of your throat. Studies suggest that they may be visible on CT scans in 16 to 46.6% of people.

Tonsil stones can get dislodged when you cough. They usually appear white or light yellow.

Tonsil stones usually don’t cause noticeable symptoms but may cause:

  • irritation in the back of your throat
  • visible white bumps on your tonsils
  • bad breath from bacterial buildup

Respiratory tract infections

Coughing up white mucus can be a symptom of a respiratory tract infection. Your body sends white blood cells toward your respiratory system to fight off bacteria or viruses. The buildup of white blood cells may turn your phlegm white.

For example, in a 2016 case study, researchers reported a man who developed white phlegm after he had a cold.

Respiratory tract infections typically also cause symptoms such as:

Most respiratory infections pass in 1 or 2 weeks and can be treated at home. Serious illnesses, such as severe COVID-19 or pneumonia, may require hospitalization.

Older adults and people with weakened immune systems are at the highest risk of developing severe respiratory infections.

Medical emergency

It’s critical to get immediate medical attention if you develop symptoms of a severe lung infection. Go to the nearest emergency room or call 911 or local emergency services if you experience:

  • bluish tinge to your skin and lips
  • confusion
  • temperature above 100.4°F
  • rapid breathing
  • severe chest pain

Chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is a group of diseases that includes emphysema and chronic bronchitis. It’s estimated to affect more than 16 million people in the United States. The majority of people with COPD have some history of smoking.

People with COPD often experience excess phlegm production. Excess phlegm can get stuck in your small airways and have a round shape when you cough it out.

Other symptoms of COPD may include:


Allergies are an overreaction to usually harmless substances such as dust or pollen. Substances that trigger allergies are known as allergens.

When allergens get in your lungs, your body may produce excessive mucus to try to get rid of them. This excessive mucus may appear as balls when you cough it up.

Other general allergy symptoms include:


Dehydration can cause your phlegm to become thicker and stickier. This might make your phlegm more likely to clump together and create round balls.

Other dehydration symptoms include:

Coughing up food

Food particles can get stuck in your throat or airways. When this happens, your lungs will produce extra mucus to remove the irritant. When you cough up a food particle, it may be covered in mucus and appear as a round ball.


Bronchiectasis is a condition characterized by permanently damaged and widened tubes leading into your lungs. It can lead to the excessive buildup of mucus that makes your lungs more vulnerable to infection. It typically causes a persistent cough that brings up phlegm. The phlegm can be clear, pale yellow, or greenish-yellow.

It can cause other symptoms such as:


People who smoke often develop a chronic cough from damage to their airways and excessive phlegm production.

In a 2020 animal study, researchers found evidence that smoking increases mucus thickness in the lungs by inducing airway dehydration. Thickened phlegm can potentially contribute to the development of balls of mucus.

Smoking can also contribute to the development of other conditions, such as COPD, that may cause you to cough up balls of mucus.

Aspergilloma and other fungi or molds

Aspergilloma, also called “fungus balls,” occurs when a ball of Aspergillus fungus grows in your lungs. These balls are made up of fungus fibers, blood clots, and white blood cells.

Aspergilloma is most common in people with weakened immune systems such as those living with AIDS or those who are undergoing cancer treatment. It may lead to coughing up brown mucus.

Other symptoms can include:

Aspergilloma is rare in the United States, with an estimated prevalence of less than 1 per 100,000 people.

Additionally, other types of fungi and molds may also lead to sputum that resembles fungus balls. These include Blastomyces, which causes blastomycosis, and Coccidioides, which causes pulmonary coccidioidomycosis (valley fever).

If you’re coughing up a ball of clear or white phlegm without any other symptoms, there’s probably no cause for concern. It’s a good idea to visit a doctor if you have a productive (wet) cough that doesn’t resolve within 3 weeks or other concerning symptoms.

It’s also a good idea to get medical attention if:

  • your symptoms are getting worse
  • you have a weakened immune system
  • you’re undergoing cancer treatment
  • you cough up blood

Treatment options for the underlying causes of coughing up balls of phlegm include:

ConditionTreatment options
Tonsil stonesgargling salt water
– manual removal
Respiratory tract infectionsantibiotics
– rest
COPD– surgery
oxygen therapy
bronchodilators and other medications
Allergies– avoiding your triggers
allergy shots
Dehydration– fluids and electrolytes
– fluids through an IV in severe cases
Bronchiectasis– surgery
– lung draining
– treating underlying conditions
– chest physiotherapy
Coughing up food– usually no treatment is needed unless you develop an infection
Aspergilloma– surgery
– antifungal medications
Smokingquitting smoking (which can be difficult, but a doctor can create a cessation plan that works for you)

What does COPD phlegm look like?

The color of phlegm in people with COPD may range from white to yellow. If you develop a chest infection, the color of the phlegm may turn a darker greenish color.

When COPD reaches an advanced stage, some people may cough up blood, or notice there is a reddish tint to their phlegm.

What is a ball of mucus stuck in your throat?

The medical term for a ball of mucus that’s built up in an airway or your throat is “catarhh.” This buildup is usually caused by your immune system that’s reacting to an infection or irritation, such as a cold or allergy.

Catarrh is typically temporary, clearing in a few days or weeks. If the condition lasts longer than that, see a doctor.

Why am I coughing up little green balls of phlegm?

Coughing up balls of phlegm that are greenish in color may be a sign of a chest infection. This is particularly true if it’s accompanied by a persistent cough, a high temperature, and rapid or shallow breathing.

See a doctor if you’re experiencing one or more of these symptoms.

Why is my phlegm so thick and sticky?

An infection can make your phlegm thick and sticky.

Infections can lead to inflammation in the mucus membranes that line your nose and airways. This can cause certain glands in these areas to produce more mucus. That mucus can then become thick and sticky with the bacteria and cells that your immune system sends to fight the infection.

Coughing up white or clear balls of phlegm can be a symptom of many different conditions. It usually doesn’t signify a serious medical condition unless you have other symptoms such as trouble breathing or a persistent cough.

It’s a good idea to visit a doctor if you have a cough that doesn’t go away after about 3 weeks or other symptoms causing you concern. A doctor can run tests to help diagnose the underlying cause of your symptoms.