Why Are You Coughing Up Yellow Mucus or Phlegm?

Key takeaways:

• Yellow mucus can sometimes be due to an infection or inflammation, but it isn’t always a cause for alarm.
• The color and consistency of your mucus can give you some clues about which health conditions may be affecting your respiratory system.
• Identifying when symptoms need professional medical care can help to prevent complications, and also detect any underlying problems that may need attention.

Coughing up yellow mucus or phlegm can be a bit unsettling, especially if it’s a new symptom. Yellow mucus usually means you are having a reaction to some sort of irritant, you have an infection, or it may mean another respiratory issue. Understanding what coughing up yellow mucus means and knowing when you should go for medical attention can help you to manage your symptoms and avoid complications. Let’s look at the common causes of yellow mucus, examine your treatment options, and discuss when it might be necessary for you to see a doctor.

Is coughing up yellow mucus or phlegm normal?

There are times when coughing up yellow mucus can be a normal part of your body’s immune response, especially if it's trying to defend itself from an infection. When fighting off an infection or an irritant, your lungs produce mucus as a defense to trap bacteria, allergens, and other particles. The yellow color often comes from the accumulation of white blood cells which have migrated to the area to target any invading pathogens. While coughing up yellow mucus is fairly common, if it continues or worsens, this could mean you have an underlying health problem that needs attention.

Causes of coughing up yellow mucus

Most of the causes of coughing up yellow mucus result from something mild, but other causes may require further follow up with your physician.

Viral infections

Viral infections, like the common cold or flu, can often lead to coughing up yellow mucus as your immune system responds to the infection. Yellow mucus often appears in the middle to later stages of an infection as your white blood cells, which have been mobilized to fight the infection, have now accumulated in the area and begin to break down within your respiratory tract.

Bacterial infections

Bacterial infections such as those causing some cases of bronchitis, sinusitis, or pneumonia can result in yellow mucus. When bacteria are involved, the mucus may thicken and take on a darker yellow color due to an increased immune response. You may have a fever, chest discomfort, or fatigue as these symptoms often accompany bacterial infections.

Allergies

Allergies to pollen, dust, or pet dander can cause yellow mucus production as your body responds to the foreign substance, known as an allergen. While allergy-related mucus usually starts out as clear, continued exposure to the allergen may lead to thicker, yellow mucus due to inflammation.

Sinusitis

Sinusitis, or inflammation of the sinuses, is another common cause of yellow mucus. As your sinuses become blocked or infected, mucus is produced and can thicken and turn yellow. If you have sinusitis, in addition to yellow mucus, you will likely have additional symptoms such as facial pain and pressure, as well as congestion.

Other causes of coughing up yellow mucus based on mucus appearance or other symptoms

Variations in color, consistency, and timing of yellow mucus production can give you some clues as to the underlying cause.

Coughing up thick yellow mucus

Thick yellow mucus is often associated with bacterial infections and/or dehydration. Thicker mucus is much more challenging to expel from your respiratory tract. Staying well hydrated by drinking plenty of fluids may help thin it out.

Coughing up light yellow mucus

Light yellow mucus is most likely a sign of a viral infection or mild irritation. While this is not generally a cause for concern, you should continue to monitor your symptoms in case they worsen or don’t go away.

Coughing up dark yellow mucus

Dark yellow mucus can indicate a more severe infection, such as bacterial bronchitis or pneumonia. If you are having other symptoms such as fever or shortness of breath, you should be seen by your physician.

Coughing up yellow and green mucus

Yellow and green mucus can indicate a lingering bacterial infection. The mucus changes color as your body continues fighting the infection. Green mucus often appears as white blood cells, sent to the area to fight the infection, start to accumulate in the area and break down.

Coughing up yellow mucus with blood

Yellow mucus with blood can result from irritation to your bronchial tree due to forceful and frequent coughing or can be due to an underlying infection. Small amounts of blood can appear when coughing, but coughing up any significant amount of blood needs medical attention. In addition, even if you see small amounts when coughing, if this persists get the advice of your physician.

Coughing up green mucus with a sore throat

Coughing up green mucus plus having a sore throat can point to a possible bacterial infection like strep throat or bacterial sinusitis. Soreness results from inflammation of your throat tissues and can often signal an infection.

Coughing up green mucus with a fever

If you are coughing up green mucus and have a fever, you may have a bacterial infection. Fever is your body’s way to fight off bacterial invaders. If your symptoms continue, or you become short of breath, you need to see your doctor.

Diagnosing coughing up yellow mucus

Your doctor may diagnose the cause of coughing up yellow mucus by doing a physical examination, reviewing your symptoms, or ordering various tests like X-rays or mucus (sputum) cultures. Cultures can help determine if an infection is bacterial or viral, and will help your health care provider choose the most appropriate treatment.

Treatment options for coughing up yellow mucus

Treatment options for coughing up yellow mucus depends on its cause. Below are common approaches to managing this symptom:

At-home remedies

In mild cases, at-home remedies can be very effective in reducing yellow mucus. Staying hydrated by drinking plenty of fluids, using a humidifier, and avoiding smoking or pollutants can help to thin mucus and reduce irritation in your respiratory tract.

Over-the-counter (OTC) medications

OTC decongestants, antihistamines, or expectorants may provide some relief, especially if the yellow mucus is due to allergies or a cold. Consult a pharmacist or your doctor to choose the most suitable medication for your symptoms.

Prescription medications

For bacterial infections, your doctor will most likely prescribe antibiotics. If acid reflux or allergies are the cause, prescription-strength antacids, H2 blockers, or antihistamines may be necessary.

When you should see a doctor about coughing up yellow mucus

While yellow mucus can often be managed at home, sometimes you need to get medical care.

You should see a doctor if:

• Your symptom persists for more than a week to ten days without improvement.
• You have additional symptoms like chest pain, fatigue, or wheezing.
• You notice significant blood in your mucus or your mucus has an unusual, unpleasant odor.

You should go to the emergency room if:

• You experience shortness of breath.
• You have chest pain.
• You see a significant amount of blood in the mucus you are coughing up.

Questions to Ask Your Doctor About Coughing Up Yellow Mucus

• What could be causing my symptoms, and do you think I should have any specific tests?
• Are there any lifestyle changes I can make that might help reduce my symptoms?
• Could any of my current medications be affecting mucus production?
• What treatment options are best for my situation?

Frequently asked questions: coughing up yellow mucus

What if you’re coughing up yellow mucus but have no other symptoms?

Yellow mucus without any other symptoms is likely harmless, especially if it’s short-lived. If this continues or you develop other symptoms, you should be seen by your healthcare provider.

What if you’ve been coughing up yellow mucus for a week or longer?

If yellow mucus goes on longer than a week, it may signal a lingering infection or another respiratory problem. You should see your doctor if your symptoms don’t improve with over-the-counter remedies.

What if you’re only coughing up yellow mucus in the morning?

Coughing up yellow mucus in the morning can result when mucus accumulates overnight, usually from a post nasal drip or sinus congestion. If your symptoms continue or become worse, get the advice of your physician.

In review

Coughing up yellow mucus is often a natural part of your body’s response to infection or irritation, and is usually manageable with rest and simple remedies. Understanding when your symptoms may require professional medical evaluation can help you avoid a worsening illness, and can also help your physician to detect any underlying problems.

General Medicine follows a strict editorial process, including using real experts to write our articles, vetted primary sources, fact-checking, a secondary medical review, and updates as necessary. This article was medically reviewed and fact checked by Dr. Lane Thaut, DO.

Sources

American Academy of Allergy, Asthma & Immunology. "Allergies Overview." AAAAI, https://www.aaaai.org/conditions-treatments/allergies/allergies-overview. Accessed 12 Nov. 2024.

American Lung Association. "Pneumonia Symptoms and Diagnosis." American Lung Association, https://www.lung.org/lung-health-diseases/lung-disease-lookup/pneumonia/symptoms-and-diagnosis. Accessed 12 Nov. 2024.

Centers for Disease Control and Prevention. "About Sinus Infection (Sinusitis)." CDC, U.S. Department of Health & Human Services, https://www.cdc.gov/sinus-infection/about/index.html. Accessed 12 Nov. 2024.

Corey, R. "Hemoptysis." Clinical Methods: The History, Physical, and Laboratory Examinations, edited by Walker HK, Hall WD, and Hurst JW, 3rd ed., Butterworths, 1990, Chapter 39. https://www.ncbi.nlm.nih.gov/books/NBK360/. Accessed 12 Nov. 2024.

Shen, F., and C. Sergi. "Sputum Analysis." StatPearls, StatPearls Publishing, 20 Feb. 2023, https://www.ncbi.nlm.nih.gov/books/NBK563195/. Accessed 12 Nov. 2024.