Hot off the press, a competent article in BMC Medicine (DNA Barcoding (BMC Medicine) Nov 2013), a public access medical website, showed that DNA testing on a variety of randomly selected herbal supplements gave dismal results. Many had contaminants or were primarily another herbal ingredient other than the one on the label. Very few appeared to have primarily if not only the herb that they were supposed to contain. And that sidesteps the more basic issue as to the proven therapeutic efficacy on herbal supplements of any sort. Such proof is, in general, either really intellectually thin, or lacking.
Should I? or May I?
Remember my concern for each of you as your physician. The Should I? issue is whether I can recommend something that you ought to do for your personal benefit. That requires data on efficacy and safety. In general, herbal products lack such confirmation, so I have difficulty saying you should take any of them.
The May I? issue is really just about safety. Could you be harmed? In general I have been relaxed about taking many herbal preparations with regard to safety. However, this study adds another level of concern that a substantial portion of herbal products bought at the usual stores contain unknown or undocumented ingredients and may not even be safe, though ineffective.
Herbal products do remain the wild West of pharmacology. I think we all need to be cautious and highly skeptical. How do we know that something works, not just hope that it works? And, by the way, these products are not cheap. Someone is making lots of money. All the more reason for skepticism about lack of data on efficacy and safety.