In October 1993, during a Senate hearing on a bill to regulate herbs, vitamins and other dietary supplements on the presumption that they were safe, Senator Orrin G. Hatch, Republican of Utah, spoke up in their defense. Herbal remedies “have been on the market for centuries,” he said, adding: “In fact, most of these have been on the market for 4,000 years, and the real issue is risk. And there is not much risk in any of these products.” That benign view was written into the bill when it was passed by both houses the following year. While the law,...