Phlegm facts for kids
Phlegm is a thick, sticky liquid made by the moist linings inside your body, especially in your breathing tubes. It's a type of mucus that comes from your respiratory system, which includes your windpipe and lungs. When you cough up phlegm, it's called sputum.
Phlegm is mostly water, but it also contains special proteins, fats, and other substances. What it's made of can change based on where you live, your family traits, and how strong your body's defense system is.
The color of phlegm can vary a lot. It can be clear, yellow, green, brown, or even dark gray. Your body naturally makes about a quart (around a liter) of phlegm every day. Its job is to trap tiny bits from the air and germs from your nose and throat. This helps keep your body clean and healthy.
Mucus and Phlegm: What's the Difference?
Many people use the words "mucus" and "phlegm" to mean the same thing, but they are actually a bit different.
What is Mucus?
Mucus is a normal, protective layer found in many parts of your body. It covers the inside of your airways, eyes, nose, and other body passages. Mucus is a sticky, stretchy gel. It's mostly water and is made by tiny glands and cells in your airways. It also contains large, special proteins that help it form long chains, making it sticky.
What is Phlegm?
Phlegm is usually linked to sickness or inflammation in your body. It's a thick liquid that builds up in your breathing tubes when you are unwell. Phlegm often contains mucus mixed with viruses, bacteria, other tiny bits, and dead defense cells from your body. When you cough up phlegm, it then becomes known as sputum.
