If you're sidelined by the flu, popping acetaminophen or ibuprofen might help you feel better in the short term, but new research shows that over-the-counter pain relievers may make you stay sick longer and be more contagious. Researchers at McMaster University in Canada determined that taking ibuprofen, acetaminophen, and similar drugs for flu symptoms can backfire in two main ways. First, most of these meds bring down fevers, which are the body's natural defense against viruses. When you disarm the body's flu-fighting weapon, the virus can linger longer.

According to lead researcher David Earn, fever suppression increases the number of annual flu cases by about 5 percent, which means more than 1,000 additional deaths per year across North America. Second, these drugs make you feel better than you actually are, so you're more likely to go to work or carry on with your normal routines. This ups your chances of passing the flu to others. Earn says you shouldn't necessarily ditch these meds. Use them only to take the edge off of painful flu symptoms—not to allow you go to work.

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