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Allergies Health Center

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The Truth About Mucus

WebMD Feature
Reviewed by Luqman Seidu, MD

Mucus is something everyone has, and some people wish they had a lot less of the stringy, gooey stuff. Sure, it can be gross to blow globs of snot into tissue after tissue when you have a cold or sinus infection, but mucus actually serves a very important purpose.

"Mucus is incredibly important for our bodies," explains Michael M. Johns III, MD, director of the Emory Voice Center and assistant professor of otolaryngology -- head and neck surgery at Emory University. "It is the oil in the engine. Without mucus, the engine seizes."

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How much mucus is normal, and how much is too much? What does its color tell you about your health? Can you just get rid of it, or at least cut down on it, and how should you do that? Here are answers.

Mucus' Mission

Mucus-producing tissue lines the mouth, nose, sinuses, throat, lungs, and gastrointestinal tract. Mucus acts as a protective blanket over these surfaces, preventing the tissue underneath from drying out. "You have to keep them moist, otherwise they'll get dry and crack, and you'll have a chink in the armor," says Neil L. Kao, MD, associate professor of medicine at the University of South Carolina School of Medicine.

Mucus also acts as a sort of flypaper, trapping unwanted substances like bacteria and dust before they can get into the body -- particularly the sensitive airways. "You want to keep that environment, which is a sterile environment," free of gunk, says Johns. "Mucus is kind of sticky and thick. It's got viscosity to it that will trap things."

But mucus is more than just sticky goo. It also contains antibodies that help the body recognize invaders like bacteria and viruses, enzymes that kill the invaders it traps, protein to make the mucus gooey and stringy and very inhospitable, and a variety of cells, among other things.

Why Am I Making So Much Mucus?

Even when you're healthy, your body is a mucus-making machine, churning out about 1 to 1.5 liters of the stuff every day. Most of that mucus trickles down your throat and you don't even notice it.

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