Thomas Cowan, MD is medical advisor to the Weston A. Price Foundation and a physician in private practice in San Francisco, California. He is the author of The Fourfold Path to Healing, which you can order from New Trends Publishing.Visit his website at http://www.fourfoldhealing.com. In our Ask the Doctor section, he takes health questions from readers and provides holistic suggestions for healing using diet, herbs, supplements, and movement.