Here's a very interesting, short interview about the role of gut microbes on everything from disease to obesity. Most have probably heard of the Human Genome Project, which maps the DNA of the human body. The scientist interviewed is working to catalog the genomes of all microbes found in and on the human body (and there are trillions, each of us actually carries more microbe cells than HUMAN cells), particularly in the gut. He's also working to treat conditions with microbes, but not via probiotics, but by actually transplanting the complete fecal microbe community of a healthy subject into one who is ill. Very intriguing, I don't know why no one thought of this before.
http://www.npr.org/templates/story/story.php?storyId=129862107
http://www.npr.org/templates/story/story.php?storyId=129862107