On a spiritual journey to the Himalayas one January many years ago I became sicker than I've ever been in my life. Wading across a chilly section of the seemingly pristine Gautam Ganga, a sacred river in the Himalayan foothills, I took a drink of the water. It was bracingly cold and delicious. It was also, apparently, a running stew of potent pathogenic microbes. With that unfortunate act I had picked up the stereotypical tourist's disease, dysentery, a grueling and potentially serious ailment that causes fever, aches, and constant diarrhea. Far from Western hospitals, I had little hope of relief. But with a mixture of local spices, an Ayurvedic doctor healed me. I was so astonished by my experience that I decided to become a professional medicine hunter--one who tracks down non-Western plants that are used as medicines. Here's how a handful of spices changed my life…