Last week, major government-funded research indicated that two wildly popular arthritis pills, glucosamine and chondroitin, did no better than dummy pills at relieving mild arthritis pain.
Earlier this month a study revealed negative results for saw palmetto to treat prostate problems; last July, ditto for echinacea and the common cold. Those followed similar disappointments for St. John's wort to treat major depression, and powdered shark cartilage for some cancers.
Of course, just because science proves that traditional remedies don't work, it doesn't follow that the public will listen.
Ben Pratt, a spokesman for the General Nutrition Centers, a national chain of stores that sell nutritional supplements, said sales of echinacea remain strong and were not affected by last summer's negative study.
You can also bet that stores that sell herbs are full of sales representatives and brochures touting the health benefits of echinacea, and that the advice that they offer to customers doesn't disclose the scientific studies to the contrary.