What Do the Colors of Kids' Phlegm Mean?

When your child isn’t feeling well, you’re probably focused on helping them feel better. Checking their phlegm? That’s likely far down on your to-do list. But here’s something you might not know—phlegm color can actually give you a clue about the type of cough your child has. 

Here’s a parent-friendly guide to kids’ phlegm colors and what they might mean:

What is Mucus or Phlegm?
The mucus is a protective fluid that lines the respiratory and digestive tracts, keeping tissues moist and blocking harmful pathogens. When your child is sick, the body produces more mucus than usual to help trap and remove germs. This excess mucus, often referred to as phlegm (when in the lungs or throat), can lead to coughing as the body works to clear the airways. It is vital to expel phlegm to remove bacteria from the respiratory tract, which results in easier breathing.

Mucus or Phlegm Color Guide

Clear Phlegm
Clear mucus helps keep the nose and airways moist while trapping dust, allergens, and germs. You’ll often see more of it when your child has a mild cold or allergies, but it’s usually nothing to worry about.

White Phlegm
Coughing up white phlegm usually means your child is dealing with some congestion—often due to a cold, allergies, or asthma. When the lining of their nose or airways becomes swollen, it slows down the movement of mucus out of the body.  As the mucus sits in the nose, throat, or chest, it begins to dry out a little and becomes thicker and stickier. That’s why it appears white or cloudy.

Yellow Phlegm
When your child’s phlegm is yellow, it usually means their body is fighting off an infection. The color comes from white blood cells rushing in to help remove the germs. It’s pretty common during the middle stages of an illness, and it often shows up before things begin to clear up. 

Just keep an eye on symptoms—especially if your little one isn’t getting better after a few days. If it lasts more than 10 days or is accompanied by a fever, consult your pediatrician. It could be a sign of an underlying disease.

Green Phlegm
Green phlegm can be a bit more concerning than yellow phlegm. When mucus turns green, it may suggest that the infection has been present for a longer period. The green color comes from an enzyme released by white blood cells that are actively fighting infection. Green phlegm should be taken seriously, especially if it’s accompanied by a fever, persistent cough, or difficulty breathing. 

Brown or Rust-Colored Phlegm 
Red or rust-colored mucus is usually a sign that there’s blood in the phlegm, often caused by irritation in the airways. Sometimes, the color is due to dried blood that’s been trapped in the mucus. 

If you notice brown or rust-colored phlegm, it's best to consult with a healthcare provider as soon as possible. A doctor will need to investigate further to rule out serious conditions.

It is natural to feel concerned when your child is dealing with phlegm—no matter what color it is. If you’re unsure, it’s a good idea to call your pediatrician. They can help determine the cause of your child’s cough and provide the best course of action. In some cases, they might even prescribe a mucolytic to thin out your child’s phlegm. 

Consider Ambroxol HCl (Expel®)! It is used for the relief of cough secondary to acute and chronic diseases of the respiratory tract accompanied by excessive lung secretions, such as chronic bronchitis, asthmatic bronchitis, and bronchial asthma.

It contains ambroxol, which helps break down mucus, resulting in thinner, less sticky phlegm. Ambroxol also aids in improving mucociliary clearance (mucus flow and transport), making phlegm easier to cough up and expel. 

Ambroxol HCl (Expel®), which can be purchased as syrup or drops, comes in a yummy orange flavor (formulated with TasteRite Technology) so it tastes better and is more appealing to kids.

Suggested Usage
Ambroxol HCl (Expel®) should be taken orally (by mouth), as recommended by the doctor.

Babies 6 months and younger:

• 0.5 mL of the 6 mg/mL oral drops every 12 hours

Babies 7 to 12 months old:

•  1 mL of the 6 mg/mL oral drops every 12 hours

Toddlers 1 to 2 years old:

• 1.25 mL of the 6 mg/mL oral drops or 2.5 mL or half a teaspoon of the 15 mg/5 mL syrup, every 12 hours

Children 3 to 6 years old:

• 2.5 mL half a teaspoon of the cough syrup every 8 hours

Kids 7 to 12 years old:

• 5 mL (1 teaspoon) of the cough syrup every 8 to 12 hours

If symptoms persist, consult a doctor.

ASC Ref No. U0154P052225E

References:
https://my.clevelandclinic.org/health/body/mucus
https://www.ncbi.nlm.nih.gov/books/NBK359/
https://www.unitypoint.org/news-and-articles/phlegm-cheat-sheet-recognizing-normal-and-concerning-colors-and-consistencies#:~:text=White%20or%20clear%20phlegm%3A%20This,bacterial%20infection%20or%20chronic%20inflammation.
https://pubmed.ncbi.nlm.nih.gov/19242860/