LAST year, Health Canada, the Canadian equivalent of the Food and Drug Administration, granted COLD-fX license to make a specific scientific claim -- something the patented American ginseng extract can't do in the U.S. The claim: Two 200-milligram doses of COLD-fX per day "helps reduce the frequency, severity and duration of cold and flu symptoms by boosting the immune system."
The Canadian agency's decision was based on positive findings from a series of well-designed studies. In one, published in the Journal of Alternative and Complementary Medicine in 2006, senior citizens who took COLD-fX for four months were 30% less likely to come down with respiratory symptoms in months three and four than seniors who took a placebo. A 2005 study of adults who took American ginseng or a placebo for four months found that those on the herb had 37% fewer colds; the results were published in the Canadian Medical Assn. Journal. Another large study of seniors, published in the Journal of the American Geriatric Society in 2004, found that the herb resulted in an 89% reduced risk of respiratory symptoms when taken for 12 weeks.
The herb hasn't been tested in children, and its ability to treat symptoms has yet to be tested.