August 2020 National Institutes of Health • Department of Health and Human Services • newsinhealth.nih.gov Inside News: 3 Chronic Health Conditions 4 Concussions 4 Finding Health Information 4 COVID-19 Network Marvels of Mucus and Phlegm The Slime That Keeps You Healthy Mucus has several names. just swallow it.” Snot, the sticky goo that The mucus, together with pours from your nose during the bacteria and other trapped a cold. Or phlegm, the gunk substances, then goes to the that can clog your lungs and stomach and eventually pass make you cough. You prob- out of the body. ably aren’t a fan of the stuff. Your body makes a lot of But mucus is so much more mucus, although no one’s than a runny nose. Your body quite sure how much. Mucus is making mucus all the time. is mostly water. But it also And it plays an important role contains special proteins, in keeping you healthy. sugars, and molecules that “Mucus and phlegm get help the body control harmful sort of a bad reputation,” says germs. Dr. Richard Boucher, a lung Usually you’re not aware expert at the University of of all the mucus that slowly North Carolina. “People think flows through your body. That about it as something you’re is, until you get sick. supposed to cough up and get out. That it’s a bad thing. But Too Much Mucus • You usu- in truth, mucus really is the ally only notice mucus when interface between you and you’re making too much of it. the outside world.” “Mucus is very important for Or if it changes consistency. Mucus lines the moist surfaces filtering out materials that you An infection can make mucus of your body like the lungs, sinuses, breathe in through your nose, thicker and stickier. Infections also mouth, stomach, and intestines. such as dust and allergens and lead to inflammation in the mucous Even your eyes are coated with a microorganisms,” says Dr. Andrew membranes that line the nose and thin layer of mucus. It serves as a Lane, an ear, nose, and throat the rest of your airway. This can lubricant to keep tissues from drying expert at Johns Hopkins University. cause certain airway glands to out. It’s also a line of defense. “Anything that you breathe in gets make more mucus. That mucus can stuck in the mucus, like flypaper.” get thick with bacteria and cells that arrive to fight the infection. That Definitions Mucus at Work • In the next hour, can stimulate even more mucus you’re going to inhale thousands of production. bacteria. But you’ll never know it. Sinuses “When mucus is particularly Bacteria land on the mucus-lined excessive, it can be bothersome The hollow spaces in your skull around surface of the lungs and get trapped. your nose, eyes, and forehead. continued on page 2 Then little hairs called cilia go to Inflammation work. They push the mucus up and Heat, swelling, and redness caused by the out of the lungs with all the trapped body’s protective response to injury or bacteria, viruses, and dust. @ infection. “It comes up at sort of a nice Subscribe slow rate to the back of the throat,” Glands newsinhealth.nih.gov Organs that produce and release Boucher says. “And if you’re normal substances into the body. and healthy, you never feel it and you 2 newsinhealth.nih.gov/2020/08 continued from page 1 in terms of runny nose, clogged “There are two general types of nose, and post-nasal drip,” says Dr. secretions that that are made in the Bruce Bochner, an allergy expert at nose,” Bochner explains. Things Wise Choices Northwestern University. Post-nasal like allergies, eating spicy food, and When There’s Too drip is when excess mucus from the being outside in the cold can result Much Mucus back of the nose gathers and drips in a more watery nasal leakage. l down the back of the throat. It’s a Your body usually makes thicker Use a humidifier or vaporizer. common cause of a cough. mucus when you have a cold (caused Keeping your nose and throat moist may reduce mucus and Allergies can also cause your body by viruses) or sinus infection phlegm production. to make extra mucus. When you (caused by bacteria). have an allergy, your immune sys- Most mucus problems are l Apply a warm, moist washcloth tem overreacts to a harmless sub- temporary. But producing too much to your face. stance, like pollen, dust, or animal mucus contributes to some serious l Try a nasal saline spray or rinse. dander. Cells in your airway then conditions. This includes cystic Clearing out mucus can help release substances, like histamine. fibrosis, a genetic disorder that you breathe easier. Commercial Histamine can make you sneeze. It causes mucus in the lungs to become products are available. If making also causes the mucous membranes thick and glue-like. Boucher and his your own, only use distilled, in the nose to swell and the glands to colleagues are working to find new sterile, or previously boiled water. make more mucus. Bochner’s team treatments for cystic fibrosis and l Consider taking over- studies how certain proteins on related lung diseases. the-counter medications. immune cells control allergies and Expectorants can thin mucus inflammation. They’re also looking Colors of Mucus • Mucus can come to help clear it from your at how certain components of mucus in a range of colors. This won’t chest. Decongestants shrink might help fight inflammation. surprise you if you’ve ever looked blood vessels, so you produce closely at your tissues after blowing less mucus. (Be careful about your nose. overusing them, as they can Definitions Mucus is normally clear. During make the problem worse.) a cold, you may find that your snot Antihistamines can help if your mucus is caused by allergies. Immune System is cloudy or yellowish. Proteins released by the cells that cause The system that protects your body from l Talk with your health care invading viruses, bacteria, and other inflammation can get stuck in the provider if your runny nose or microscopic threats. mucus and give it this color, Lane congestion lasts more than three explains. He’s currently studying weeks or occurs with a fever. how cells in the nose and sinus are NIH News in Health involved in long-term inflammation, ISSN 2375-6993 (Print) ISSN 1556-3898 (Online) called chronic sinusitis. wouldn’t want to go without mucus. Editor Harrison Wein, Ph.D. Brown or black mucus is more “Mucus creates a layer of Managing Editor Tianna Hicklin, Ph.D. common in heavy smokers and some protection between the outside Graphics Alan Defibaugh (illustrations), types of lung disease. Greenish, world and you. So it’s very, very Bryan Ewsichek (design) brownish, or bloody colors may important,” Lane says. Contributors Erin Bryant and Heather Martin signal a bacterial infection. It’s not just important for people. Use our articles and illustrations in your own But that’s not always the case. It It’s also the slime that allows a snail publication. Our material is not copyrighted. can be difficult to figure out what’s to move across the ground. It’s the Please acknowledge NIH News in Health as the wrong simply by your mucus color. slippery coating that protects fish source and send us a copy. Since many things can cause your against bacteria in the water. “It’s a body to make too much mucus, really wonderful material,” Boucher newsinhealth.nih.gov doctors rely on other clues to says. diagnose and treat the problem. But maybe your mucus isn’t feeling so marvelous. If excess mucus is get- NIH…Turning Discovery Into Health® Wonders of Mucus • While excess ting you down, see the Wise Choices snot and phlegm aren’t pleasant, you box for tips on getting rid of it. n Office of Communications & Public Liaison Building 31, Room 5B52 Bethesda, MD 20892-2094 For more about mucus and phlegm, email: [email protected] Web see “Links” in the online article: phone: 301-451-8224 Links newsinhealth.nih.gov/2020/08/marvels-mucus-phlegm 3 newsinhealth.nih.gov/2020/08 Chronic Disease in Uncertain Times Be Prepared and Plan Ahead Coping with emergencies is chal- follow the CDC’s latest public lenging in the best of situations. health guidance. That awareness During the coronavirus pandemic, is especially important in a many of us are just trying to get by pandemic. As we’ve seen with each day. For people with chronic COVID-19, information about (long-term) health conditions—like new diseases can quickly change. diabetes and chronic kidney dis- Rodgers also says it’s important ease—the challenges can be even to keep in touch with your health greater. But with planning, you can care providers. They can help prepare what you’ll need to make you to adapt and maintain your things more manageable. normal disease management “Thankfully, people with chronic plans. medical conditions have tools to help Be sure to eat well and safely maintain their health, even during participate in physical activity difficult times,” says Dr. Griffin P. as much as possible during these Rodgers, director of NIH’s National difficult times. That can help you Institute of Diabetes and Digestive prevent or delay health problems. and Kidney Diseases. Managing Some people with chronic these conditions well can help lower conditions need to follow a your risk for complications and other special nutrition plan. For diseases. example, people with diabetes Keeping on top of health problems should follow a healthy eating can take extra effort during plan prescribed for blood sugar uncertain times.