He's not just getting a cold. He's building his microbiome. iStockphoto.com hide caption

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Say hello to your microbiome, Rob Stein. Our intrepid correspondent decided to get his gut bacteria analyzed. Now he's wondering if he needs to eat more garlic and onions. Morgan Walker/NPR hide caption

itoggle caption Morgan Walker/NPR

Hydrocodone, sold as Vicodin and other brand names, may face tighter restrictions on prescribing and use. Toby Talbot/AP hide caption

itoggle caption Toby Talbot/AP

This micrograph shows a single mitochondrion (yellow), one of many little energy factories inside a cell. Keith R. Porter/Science Source hide caption

itoggle caption Keith R. Porter/Science Source

Knight (left) and Bucheli take soil samples from beneath one of the decomposing bodies. Katie Hayes Luke for NPR hide caption

itoggle caption Katie Hayes Luke for NPR

The Eagle Mountain Church in Newark, Texas, was linked to at least 21 cases of measles this year, mostly in children. LM Otero/AP hide caption

itoggle caption LM Otero/AP

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

itoggle caption Toby Talbot/Associated Press

Billie Iverson, 86, of Cranston, R.I., recently underwent a transplant of intestinal microbes that likely saved her life. Ryan T. Conaty for NPR hide caption

itoggle caption Ryan T. Conaty for NPR

We may not see them, but we need them. iStockphoto.com hide caption

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