What Are the Most Common Causes of Brown Phlegm?

Exposure to air pollution may cause brown phlegm.
The respiratory system.
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  • Written By: Christina Edwards
  • Edited By: W. Everett
  • Last Modified Date: 16 April 2014
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Phlegm is the thick, sticky mucus that is usually expelled out of the body through coughing. It can come in a number of colors, such as white, yellow, green, and brown. Many times, the color of phlegm can give clues that can help make a diagnosis of certain respiratory problems. Brown phlegm can be relatively harmless when it is caused by food, but sometimes it indicates an underlying health problem caused by smoking, air pollution, or illnesses including cancer and emphysema.

Certain foods and drinks can cause a person's phlegm to appear brown. This is usually harmless, although it can worry some individuals when the color of their phlegm is darker than usual. Chocolate, red wine, and dark sodas can all cause brown phlegm.

Dust and dirt can also possibly cause brown phlegm. When cleaning a dusty room or working around blowing sand or dirt, tiny particles can get caught in the throat. This mucus will then be coughed up, and the resulting phlegm will appear brown and grainy.

Smoking is one of the most common causes of brown phlegm. This happens because the resins, tars, and other toxic chemicals become trapped in the lungs. Heavy smokers will often cough up a small quantity of brown mucus, especially in the morning.


Individuals who are trying to quit smoking usually cough up large quantities of brown phlegm as well. After a person quits, the cilia in the lungs, which are often damaged by smoking, begins to work at its full potential again. These tiny hair-like projections then begin to sweep out the large quantities of phlegm caught in the lungs. This can last for months in some individuals.

Individuals who live in areas with very polluted air can also cough up brown phlegm from time to time. Prolonged exposure to certain air pollutants can cause a variety of chronic illnesses. Some of these illnesses include bronchitis, emphysema, and cancer.

Certain respiratory or lung infections are more serious causes of brown phlegm. Coughing up phlegm is the body's way of getting rid of excess mucus in the lungs. Usually when a person gets a respiratory illness, the lungs will begin to produce more mucus than normal to trap certain bacteria and other foreign matter.

Brown phlegm is a common sign of chronic bronchitis. Individuals with other more serious respiratory infections, such as lung cancer or emphysema, can also cough up brown phlegm. Usually the exact cause of brown phlegm can only be determined by a physician.


Discuss this Article

Post 9

After years of smoking and chewing tobacco, my grandfather developed emphysema. Though he lived into his eighties, he suffered a good deal while trying to breathe.

He kept a jar by his recliner into which he spit the brown phlegm that he coughed up on a regular basis. His voice had become hoarse and weak from all of the coughing, and it really tired his whole body out.

I always had a sense of doom when I went to see him. That rattling cough and the resulting dark phlegm told me that he wouldn’t last much longer on this earth.

Post 8

When my husband and I rented our first house, we had to go in and do some major cleaning to get it ready. One super dusty area we had to tackle was the utility room attached to the garage where our washer and dryer would go. Since it was outdoors, it had layers of dirt built up on the shelves and tons of cobwebs in corners.

Had I known what it would do to me, I would have worn a mask while cleaning it. We stirred up the dust and dirt into the air, and we breathed it in. Immediately, I began coughing. By the next day, I was hacking up brown phlegm. I developed an infection that required antibiotics, and the brown phlegm persisted for a couple of weeks.

Post 7

I never knew that what I ate and drank could colorize my phlegm. I guess I just assumed that since food goes through the digestive system and phlegm goes through the respiratory system that the two never met.

I do drink dark sodas, and I eat a substantial amount of chocolate. So, when I got bronchitis, which already makes you have brown phlegm, mine was extra brown. It freaked me out when I first saw it, because I thought it might have dried blood in it.

My doctor reassured me that the color of my phlegm was normal for someone with my diet and disease. I felt better knowing that I was not bleeding internally!

Post 6

My husband recently got an upper respiratory infection. He began coughing up brown phlegm. He thought he had strep throat because it hurt so much to swallow, but the nurse practitioner told him it was a different kind of infection.

I’m sure his phlegm was even browner than that of most people who get respiratory infections, because he is a smoker. The nurse practitioner told him he really needs to quit, because smoking is an irritant. It takes him longer to recover from respiratory illnesses because of his smoking habit. He will be coughing up brown phlegm for longer than normal after the infection leaves his body.

Post 4

@janeAir - My mom used to ask us that too when we were kids. She always wanted to make sure our phlegm wasn't green, because that means infection.

It sounds like in some cases, brown phlegm is worse than green. I think I would definitely rather have some type of infection than lung cancer or emphysema.

Post 3

When I was younger, whenever I had a cough my mom would always ask me what color my phlegm was if I was coughing any up. I always thought this was really gross!

However, as usual, mother knows best. Like the article said, the color of the phlegm can tell you a lot about what is wrong. For example, one of my great aunts had lung cancer. One of the first symptoms she showed was coughing up brown phlegm.

Post 2

@lonelygod - Even if your mother doesn't have lung cancer it certainly sounds like something more is going on than just a regular smoker's cough. My grandmother had the same thing and she found herself constantly getting lung infections like bronchitis.

If your mother thinks that something is wrong it is really best that you make sure she sees a doctor. Smoking can have a lot of negative long term health effects, but that doesn't mean she shouldn't still see the doctor when her brown phlegm gets worse. It really is better to be safe than sorry. If it is just from her smoking, so be it. But I think your whole family would feel better knowing what is really happening.

Post 1

My mother has been a heavy smoker her whole life but has recently noticed an increase in the brown phlegm she is producing and is worried that something may be going wrong with her lungs. We have tried to get her to quit smoking for years but to no avail.

Do you think that an increase in phlegm is a natural part of being a long-term smoker, or that there may be something more dangerous happening?

We are really worried she might have given herself lung cancer with all the puffing away she's been doing over the years. It is upsetting to think of how easily this all could have been avoided.

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