Yellow phlegm can be a sign that a person has an underlying infection or illness. This illness may cause a person with asthma’s symptoms to become worse. A person with asthma should be conscious of the color of their phlegm, as certain colors may mean they should contact a doctor. They should also monitor their asthma symptoms closely.

Phlegm is a thick mucus that is sometimes known as sputum and is different from saliva. People cough up phlegm from their lungs.

The body can produce excess phlegm when a person has certain illnesses. Different illnesses and conditions can cause the phlegm to become different colors.

This article will explain the possible causes of yellow phlegm in people with asthma. It will give treatment options for these causes and advise when a person should contact a doctor.

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Some people with asthma produce excess phlegm, but yellow phlegm could be a sign of infection.

Phlegm production of any color can be a sign that the person’s airways are becoming inflamed. This may also cause other asthma symptoms to arise, such as:

If a person’s airways become too inflamed, they may narrow and cause an asthma attack. In this instance, a person can use a rescue inhaler to expand their airways and make breathing easier.

Yellow phlegm is not normal and can be a sign that an infection is present.

Yellow or green phlegm may be a sign that a person has developed an infection. This could include:

Infections often worsen the symptoms of asthma, which can be dangerous. This is why it is important that a person with asthma keeps using their preventer inhaler to control their symptoms.

Yellow phlegm can also be a sign that a person has developed a number of illnesses. Yellow phlegm may turn to green phlegm over time. This is due to the illness becoming worse, and more white blood cells and debris in the mucus.

Below are some common illnesses that cause a person to produce yellow and green phlegm:


Bronchitis causes swelling and inflammation in the bronchial tubes, which link the mouth and nose with the lungs. Initially a person may develop a dry cough, which can cause clear or white phlegm to develop.

Over time, the phlegm may turn yellow or green. This may be a sign that a secondary bacterial infection has developed.


Pneumonia is an infection of the lungs that has a variety of different possible causes. Pneumonia causes the lungs to become inflamed and causes alveoli inside the lungs to fill up with fluid.

A person with pneumonia may cough up phlegm that is yellow or green.


Sinusitis is the name for the inflammation of the sinus or nasal passages. Causes of sinusitis can include viruses, bacteria, fungi, allergies, and an autoimmune reaction.

A common symptom of sinusitis is yellow or green phlegm and nasal discharge.

Yellow phlegm can mean that a person has a specific illness. These illnesses can also cause a number of other symptoms to appear.

Other symptoms of bronchitis

As well as the production of yellow or green phlegm, bronchitis can cause a variety of other symptoms. Symptoms of acute bronchitis last longer than 3 weeks and include:

Learn more about the symptoms of bronchitis here.

Other symptoms of pneumonia

Yellow or green phlegm is a common symptom of pneumonia. Other symptoms include:

Learn more about what pneumonia can feel like here.

Other symptoms of sinusitis

Sinusitis is the name for a number of sinus infections. Yellow or green phlegm is a common symptom of sinusitis. Other common symptoms include:

Learn more about sinus infection symptoms here.

A doctor may treat illnesses that can cause yellow phlegm in a variety of ways.

Treatment for bronchitis

Doctors may advise people with bronchitis to get plenty of rest and drink lots of fluids.

They may also suggest they take over-the-counter (OTC) medications such as ibuprofen or cough medicine. This can relieve the cough and ease any pain associated with bronchitis.

Other treatments for bronchitis include:

  • bronchodilators, which open up the bronchial tubes and may help clear out mucus
  • anti-inflammatory or steroid drugs to reduce inflammation
  • the use of a humidifier to loosen mucus, improve airflow, and relieve wheezing

Learn home remedies for bronchitis and when to contact a doctor here.

Treatment for pneumonia

People with asthma have an increased risk of developing pneumonia. This is because asthma causes lung damage or weakness of the lung tissue. The American Lung Association states that pneumonia is a leading cause of hospitalization in children and adults with asthma.

Depending on the type and severity of the person’s pneumonia, a doctor may choose a variety of treatments.

Doctors often treat viral pneumonia with rest and plenty of fluids as well as some antiviral medications.

Healthcare professionals most commonly treat bacterial pneumonia with antibiotics and use antifungal medications to treat fungal pneumonia. They may also prescribe OTC medications to manage the symptoms of pneumonia. These medications can reduce fever, stop headaches, and suppress coughing.

It is important that a person who has pneumonia gets plenty of rest and drinks lots of fluids.

Learn ways to ease symptoms of pneumonia here.

Treatment for sinusitis

If the symptoms of sinusitis persist or become severe, a doctor may prescribe drugs to treat the condition.

If they believe that a bacterial infection is present then they may also prescribe antibiotics.

If a person has chronic sinusitis, then a doctor may suggest that a person reduces their exposure to things that may cause sinusitis to flare up. This includes avoiding allergens such as dust mites and pollen.

A doctor may also wish to manage the person’s inflammation with corticosteroid sprays or tablets. However, long-term use of these may cause adverse effects.

If other treatments do not work, then a doctor may decide to use surgery to treat sinusitis.

Learn treatments and home remedies for a sinus infection here.

The color of phlegm can tell a lot about the condition of a person’s respiratory system. Below is an outline of some of the colors and what they mean.

Clear phlegm

Healthy phlegm is usually clear. However, if a person produces large amounts of clear or white phlegm then it may be a sign that their airways are inflamed.

Large amounts of clear or white phlegm may also mean that a person’s asthma symptoms are getting worse.

A person may wish to use their preventer inhaler to deal with worsening asthma symptoms.

Brown phlegm

Brown phlegm often appears in people who smoke. It could mean that there is dried blood present in the mucus.

Brown or rust-colored phlegm can also mean that bacterial pneumonia or bacterial bronchitis may be present.

White phlegm

White phlegm may be a sign that a person has nasal congestion. This can cause the mucus to pass through the respiratory tract slower, which can cause mucus to become thicker and white in color.

White phlegm may also be a sign that the following conditions are present:

Red or pink phlegm

The main cause of red or pink phlegm is the presence of blood. A person may have blood in their phlegm if they have been coughing a lot due to a respiratory infection.

There are a number of other conditions that can cause blood to be present in a person’s phlegm. These include:

Black phlegm

Medical professionals sometimes refer to black-colored phlegm as melanoptysis. This can be present if someone has inhaled large amounts of something black, like coal dust.

Smoking cigarettes may also cause black phlegm.

Fungal infections can also cause black phlegm.

Learn more about the different colors and textures of phlegm here.

If a person with asthma has phlegm that turns yellow or green then they may want to wait a few days to see if it returns to normal. However, if it remains yellow or green for more than a few days then they should make an appointment with a doctor.

They should also monitor their other asthma symptoms just in case they begin to get worse.

If a person with asthma’s phlegm turns red, brown, or black, then they should speak to a doctor right away, even if they only notice a little of these colors. This is because it could be a sign that a more serious condition is present.

Phlegm is a thick mucus that the body produces. It is sometimes known as sputum. People cough up phlegm from their lungs and respiratory tract.

A person with asthma may produce excess phlegm. If a person with asthma produces yellow phlegm, it may be a sign that an infection or other condition is present. Common conditions that cause phlegm to turn yellow include pneumonia, bronchitis, and sinusitis.

A person should contact their doctor if they have been producing yellow phlegm for more than a few days.

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