Breathing exercises as effective as prescription drugs? Guided imagery and herbs dispensed as painkillers? Andrew Weil’s approach to health and well-being has won him a following of millions and at the same time put the American medical establishment on red alert.

An advocate of nutritional supplements, meditation, yoga, and other mind-body remedies and regimens, Weil, thanks to his impeccable training and eclectic approach, is partly responsible for bringing these therapies from the margins to the mainstream. His method is to encourage people to blend conventional and alternative treatments. In managing diseases like cancer, for instance, he often subscribes to traditional modalities offset by therapies that reduce a drug’s toxicity (and maybe also increase its effectiveness). The result is what he calls “integrative” medicine.