When a medical crisis hits, people want to know that someone smart in a white coat can prescribe Prozac to boost their mood, perform heart surgery to open their clogged arteries, or administer chemotherapy, radiation or surgery to cure them of cancer. But growing numbers of Americans are also eager to experiment with alternative therapies. A natural tension has long existed between these two kinds of medicine. Western medical practitioners have been wary of the sometimes wacky-sounding, often-untested therapies in alternative medicine's toolkit. Alternative medicine practitioners have typically operated outside the conventional system, with consumers paying out of pocket. But over the last 10 years this wall has started, partially, to erode. Aided by federal funds, an increasing number of alternative therapies have been put to Western-style clinical tests, separating ones that seem beneficial, such as acupuncture for relief of pain, meditation to reduce hypertension, or ginger to relieve nausea -- from the chaff that appears ineffective. And conventional practitioners have come to appreciate the effect of the mind on chronic pain, heart disease, autoimmune conditions, anxiety and depression -- even the progress of disease.