PHLEGM FACTS - The Washington Post

Q. My question may seem a little gross, but I know several people who would like to know the answer. When you have a cold, is it okay to swallow the phlegm that drips down the back of your throat or is coughed up from your rattling lungs? A. Sometimes I use a tissue, but what if one isn't handy? Although I think spitting is disgusting, I wonder whether it isn't a healthier alternative to swallowing. And if you do swallow, does it get recycled and come back around a second time? Does it prolong the illness, or possibly lead to infection or complications in other parts of the body?

Phlegm is the thick mucus made by your nose, sinuses and lungs, often in response to infections like the common cold. The idea that phlegm is harmful is basically folklore. But you're certainly not alone in believing that you should avoid swallowing phlegm during an illness.

I think this notion goes back to ancient times, when people discovered that eating spoiled foods or toxic substances could make you sick. It made sense that if you could get rid of the toxin by spitting it out or purging yourself of it, you might get better.

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In the Middle Ages, people's health and temperament were thought to be due to a balance of the four humors or body fluids -- blood, phlegm, yellow bile and black bile. Until modern times, a common medical practice was bloodletting. In some cases, this procedure was based on the false notion that removing "toxin-laden" blood would remedy the illness.

In a similar way, some people think that phlegm is toxic, and that ridding the body of it will speed recovery. This notion is reinforced by the very words we use to describe a common cold. Some people call phlegm "cold" and imply that spitting up the "cold" will help rid your body of your cold.

In fact, there's a large industry of cough medicines that caters, in part, to the belief that if you could just "cough it up" you would mend faster. And to take it a step further, some people mistakenly believe that exposure to cold temperature causes their cold. Some even think that the "cold" or phlegm travels through their body causing infection, symptoms or other problems. For example, some people with a cold and muscle aches in their side mistakenly believe that the "cold" has settled in their kidney.

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So, to answer your questions: The phlegm itself isn't toxic or harmful to swallow. Once swallowed, it's digested and absorbed. It isn't recycled intact; your body makes more in the lungs, nose and sinuses. It doesn't prolong your illness or lead to infection or complications in other parts of your body.

Finally, it's actually beneficial to swallow some viruses. That's because your intestines help make disease-fighting antibodies against certain viruses. The polio virus is a well-known example; that's why the standard polio vaccine is an oral vaccine instead of a shot. Jay Siwek, a family physician from Georgetown University, practices at the Fort Lincoln Family Medicine Center and Providence Hospital in Northeast Washington. Consultation is a health education column and is not a substitute for medical advice from your physician. Send questions to Consultation, Health Section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. Questions cannot be answered personally.

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