Phlegm Cheat Sheet: Recognizing Normal and Concerning Colors and Consistencies

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Phlegm, the ooey gooey gook living in your upper respiratory system, gives helpful clues about what’s going on with your health. Brian Lindsay, MD, UnityPoint Health decodes the different textures and colors of phlegm, explaining what might be happening in your body and when the look and feel of phlegm is concerning.

What is phlegm?

Dr. Lindsay says phlegm is a type of mucus, a sticky fluid found in the upper respiratory tract — an area of the body that includes the trachea, pharynx and lungs.

The difference between phlegm and mucus is that phlegm is produced by the respiratory tract, while mucus is present in the respiratory system and elsewhere, such as the digestive and reproductive system.

“Mucus is made up of electrolytes and proteins, and it’s part of our normal immune defenses. Our body uses it to lubricate the respiratory tract to capture things like bacteria, so it doesn’t get into our body. Overall, phlegm is our friend. It helps protect our body from infections,” he says.

Our bodies are always making phlegm, but people only notice it when their body is making an excessive amount, or they have a productive cough and phlegm comes out.

What causes phlegm?

Dr. Lindsay says both acute and chronic conditions produce phlegm. Some common acute conditions include:

Some chronic conditions that cause the body to produce more phlegm include:

  • Allergies
  • Sinusitis
  • Chronic Obstructive Pulmonary Disease (COPD)
  • Asthma and related conditions that fall under the umbrella of inflammatory lung diseases

“Another common condition that can be acute or chronic, where people cough and bring up phlegm, is gastroesophageal reflux (GERD),” says Dr. Lindsay. “This is where acid from the stomach irritates the upper airways, so the body produces more phlegm as an act of protection against the acid. The person experiencing it can feel the phlegm in their throat and want to clear it out by coughing. Phlegm also tends to feel like it’s constantly in your throat, in this case.”

Dr. Lindsay says when other causes have been ruled out and acid reflux is the diagnosis, the proton pump inhibitors prescribed typically take a few months to start working.

For chronic conditions that cause phlegm, Dr. Lindsay says a telltale sign of poorly controlled, or exacerbated, asthma is when a person coughs up hard, sticky chunks of phlegm. Symptoms of chest tightness, wheezing or shortness of breath typically accompany the uptick in phlegm, too.

He adds there’s no one-symptom-fits-all approach to inflammatory lung diseases, like asthma or COPD.

“Some people who have COPD don’t have much of a cough or cough up much phlegm. The big thing to pay attention to is if you don’t normally cough up a lot of phlegm — then all of a sudden you are — that’s concerning and something you should talk to your pulmonologist or primary care doctor about,” he says.

What does the color of my phlegm mean?

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The color of your phlegm can tell you what’s going on with your respiratory health. Different colored hues may signify different conditions or infections affecting your respiratory system.

White or clear phlegm: This is normal.

White phlegm with yellowish tint: It could be normal or signal an infection or inflammation.

Yellow or dark yellow phlegm: It could mean a viral or bacterial infection or chronic inflammation.

Green phlegm: It could mean a viral or bacterial infection or chronic inflammation.

Pink phlegm: It could mean heart failure.

Red phlegm: Bloody phlegm can come from the nose or lungs and signal irritation, infection or cancer.

Dark brown phlegm: This is concerning for an infection, such as bacterial pneumonia.

Gray phlegm: This is likely normal and tends to be a variation of white phlegm.

Black phlegm: This is rare, but it can mean old blood or be from something you inhaled.

Dr. Lindsay says coughing up blood is alarming but assures a bloody cough doesn’t always mean cancer.

“More often than not, it ends up not being cancer. However, it’s not something we ever mess around with. You should see your doctor right away if you’re coughing up red phlegm,” Dr. Lindsay says.

“You’ll likely need a chest x-ray or CT scan to determine the cause and rule out anything sinister."

Phlegm from pneumonia can be a dark brown or a vibrant yellow or green, and “it just looks gross,” Dr. Lindsay says.

“If you look at it, and it makes you go, ‘eww,’ or it has a foul taste to it, there’s a good chance the cause of the phlegm is from bacterial pneumonia. You kind of know it when you see it.”

What does the consistency of my phlegm mean?

Like the color of your phlegm, the texture and consistency can provide insights into what’s happening in your body. Clear phlegm with bubbles, or phlegm that’s semi-solid to almost liquid, is normal. Phlegm with sticky, hard chunks, however, is likely a sign of uncontrolled asthma or another type of COPD.

How to get rid of phlegm

The best way to get rid of phlegm is to treat the source of it. For instance, if you’re asthmatic, getting your asthma under control helps get rid of excess phlegm production. If you have a bacterial infection, an antibiotic helps take care of the phlegm.

If excess phlegm is more bothersome at night, Dr. Lindsay says it could be acid reflux. Taking medication and/or lifestyle modifications like cutting back on alcohol and caffeine, not going to sleep on an empty stomach or sleeping with your head elevated can help reduce or eliminate phlegm.

Other lifestyle modifications to help get rid of phlegm from the lungs include staying hydrated or using a humidifier, especially in the winter months when the air is drier.

Dr. Lindsay also suggests cutting out dairy products, which produce phlegm in our bodies.

What does throwing up phlegm mean?

Dr. Lindsay says it’s tricky to determine the cause when patients believe they’re throwing up phlegm.

“There’s mucus in the stomach, and if you throw up on an empty stomach, you may notice some of that mucus coming out. In my experience, most people who say they're throwing up phlegm are actually having a severe cough and feel like they have to cough hard to get the phlegm out.”

“It doesn’t necessarily mean anything bad,” he says. “It’s just uncomfortable.”

When to see a doctor about phlegm

Dr. Lindsay advises, “What it comes down to is whether the phlegm is a change in what’s normal for you. Even if it looks fine, but you don't normally cough up a lot of phlegm and you now are, talk to your doctor. Just because it's white or clear doesn't mean it's nothing.”