I heard this story on NPR yesterday morning about infants and the use of GERD medication to control chronic "spitting up." Apparently, the same PPIs administered to adults being used off-label to treat babies with some success.
When I first heard this, I thought, "Sounds like uber-worried parents -- don't all babies spit up and get fidgety?" After reading the rich comments section, though, I am much more sympathetic. It sounds similar to what adult GERD sufferers can endure at their doctors' offices: "But SOMETHING is going on -- it's not in my head."
I'd be apt to try the non-medication route first, though -- changes in diet as well "lifestyle" changes (being sure to burp the baby, feeding smaller portions to match an infant's stomach size).
KIDS AND GERD LINKS
Here's North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN)'s website about GI issues and kids: http://www.gastrokids.org/content/8/en/Reflux-GERD
From KidsHealth, a page for kids about GERD: http://kidshealth.org/kid/health_problems/stomach/gerd.html
Pediatric capsule endoscopy is explained on the NewYork-Presbyterian Komansky Center for Children's Health's Gastroenterology page.