Nearly one in fifteen people--that's 20 million people in the United States--suffers from peripheral neuropathy, or nerve damage. Caused by such conditions as diabetes, cancer, vitamin deficiencies, and kidney disease as well as certain drugs and toxins, neuropathy brings numbness, tingling, and burning in the feet, legs, and fingertips. Neuropathy can be more than uncomfortable--it can be disabling: people whose fingertips are numb may find it hard to button clothing and complete other everyday tasks. Neuropathy is often dangerous, as well: people who cannot feel their feet are more...