The cough reflex is a function of the motor section of the brain. When one laughs, small particles of saliva can enter the upper respiratory system, triggering the cough reflex, which uses mucus as a means to protect the lungs from pathogens, particles, and exposure to toxic chemicals.

The brain interprets saliva in these instances as being a foreign substance that could potentially harm the lungs. This is why one might find mucus, or phlegm, in the throat after laughing. This is especially true when one has a hypersensitive cough reflex.

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Phlegm’s Function in the Human Body

The body creates a lot of phlegm; however, the exact amount is unknown. It consists primarily of water, but it also contains other important elements, such as sugars, special proteins, and molecules to aid in the prevention of harmful germs.

The word “phlegm” stems from an ancient Greek belief that mucus is caused by heat.

Mucus, or phlegm, is a type of fluid that appears in numerous places in the body but is mostly secreted by the airways of the lungs. If it’s coughed up during an infection or because of irritated mucosa, it’s known as “sputum.”

This substance is often used in medical analysis and for diagnostic purposes because it contains a variety of molecular compounds, such as specific types of proteins and soluble lipids that are crucial to medical analysis.

Examining it can help medical professionals determine what is going on with a patient’s upper respiratory tract. It is also used to help doctors evaluate and manage lower respiratory infections and other types of health conditions. Examination of this substance has helped increase the accuracy of medical diagnosis.

Phlegm in the Throat

Phlegm can become present in the throat for various reasons. For instance, it shows up as a symptom of allergies (e.g., allergic postnasal drip). Influenza and certain colds can increase phlegm production in the throat, as can breathing in too much dry air.

An excess amount of phlegm sometimes appears when one has a sinus infection. It can also be triggered by the fumes given off by certain cleaning products. Environmental irritants can have the same effect, as can certain chemicals or cigarette smoke, and other irritants.

When the sinuses become inflamed, phlegm can appear in the throat. A deviated septum can also cause it in this area, and some women experience it during pregnancy. Certain blood pressure medications cause it, as do birth control medication and some types of foods, such as cuisines that are too spicy.

The cause of phlegm in the throat is indicative of whether or not it is a cause for concern about one’s health.

Phlegm’s Color Can Indicate Illness

The color of the phlegm that is produced can inform medical professionals a lot about a patient’s condition. For instance, it may appear as any of the following colors:

  • Clear
  • White
  • Yellow
  • Green
  • Pink
  • Red
  • Brown
  • Black

In general, each color corresponds with a different type of health issue.

Mucus Phlegm Color Guide Chart

Phlegm that appears yellowish or green is often associated with certain infections. However, the color does not always indicate the specific type of infection. Therefore, upon discovering this type of phlegm, one should make an appointment to see a physician who can render a diagnosis based on test results, the duration of the condition, and exposure to others who have been ill with certain symptoms.

If the phlegm appears to be various shades of red or pink, a physician should be consulted immediately. This color phlegm could also be caused by an infection of some type, but it could also be an indication of the presence of certain types of cancer. This is especially concerning for smokers.

When the phlegm appears opaque white in color, it could be contributed to asthma, allergies, or certain types of viral infections. If the white phlegm appears due to some underlying condition, such as COPD or asthma, this could be an indication that the primary cause is not controlled.

White phlegm that is produced as the result of an upper respiratory tract infection will usually go away on its own. If it is associated with allergies, a more potent allergy regimen might be in order.

Light gray or phlegm that appears black or deep gray may appear because the person displaying it is a heavy smoker or works in a dusty environment, such as a coal mine. This can be an inflammatory reaction that causes the airways to manufacture phlegm, or it can be indicative of an infection of some type that should be diagnosed by a physician. Steroids or antibiotics are often prescribed in these cases.

The existence of a chronic lung disease can result in phlegm that is a brownish color. When it is very dark, it could indicate the presence of a chronic lung disease called bronchiectasis. It could also be a symptom of cystic fibrosis.

Chronic inflammation and blood are the cause of the odd coloration of this type of phlegm, as well as the bacteria that appears outside of the lungs.

Phlegm’s Appearance After Laughter

Hard laughing can cause saliva droplets to enter the windpipe. Since phlegm is produced as protection against infections and other foreign particles, the brain can interpret the presence of saliva in the windpipe as a foreign substance from which the body needs protection.

Therefore, it produces phlegm, which can tickle the throat and potentially cause one to cough as the body attempts to eject the foreign substance.

Asthma can also cause phlegm to appear in the throat after someone laughs, which results from several different triggers. When a person with asthma laughs, their airways may constrict, resulting in an asthma attack. This causes bronchoconstriction and may even result in increased phlegm production.

Final Thoughts

Even though it might be embarrassing to have phlegm dripping down the back of your throat after a fit of laughter, it is actually a natural and normal response from the body.

The three primary reasons that phlegm can appear in the throat after laughing include:

  1. Aspiration of saliva
  2. Post nasal drip
  3. The presence of asthma

In most cases, it is nothing to worry about and will go away on its own. However, if the phlegm is a strange color or if it is accompanied by other symptoms, it is important to see a physician to rule out any underlying causes. Thanks for reading, and, as always, breathe easy, my friend.

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.

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Medical Disclaimer: The information provided by Respiratory Therapy Zone is for educational and informational purposes only. It should not be used as a substitute for professional medical advice, diagnosis, or treatment. Please consult with a physician with any questions that you may have regarding a medical condition.