Streptococcus pyogenes shouldn't be taken lightly. Left untreated, an infection with germ can trigger an autoimmune disease that damages the heart. NIAID/Flickr.com hide caption

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Drug overdose deaths have more than tripled in the U.S. since 1990. Opioid painkillers like OxyContin are the cause of three-quarters of those deaths. Toby Talbot/Associated Press hide caption

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The active ingredient in Propecia, a baldness remedy approved by the Food and Drug Administration in 1997, is showing new promise as a way to prevent some prostate cancers. AP hide caption

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When dealing with aches and pains, sometimes the best way to get better is to feel better — and fast. Some popular medicines of old favored additives like cocaine. Courtesy of the National Library of Medicine hide caption

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How does the doctor decide what to write on the prescription pad? iStockphoto.com hide caption

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