You tried burping. You tried bouncing. You tried swaddling. Now what? iStockphoto hide caption

itoggle caption iStockphoto

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

Microbiologist Emma Allen-Vercoe invented the Robogut, a mechanical device that mimics conditions in the human colon. Courtesy of thestar.com hide caption

itoggle caption Courtesy of thestar.com

Packages of Activa yogurt, which contain probiotics, on a grocery shelf in Chicago. M. Spencer Green/AP hide caption

itoggle caption M. Spencer Green/AP