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DNA barcoding detects contamination and substitution in North American herbal products

Steven G Newmaster*, Meghan Grguric, Dhivya Shanmughanandhan, Sathishkumar Ramalingam and Subramanyam Ragupathy*

BMC Medicine 2013, 11:222  doi:10.1186/1741-7015-11-222

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Criminal behavior needs greater disclosure by the authors.

s bear   (2013-11-28 15:24)  National Library of Medicine (retired)

On the one hand I am grateful for attempts to clean up corruption of adulterated herbs.  On the other hand when accusation of a criminal level of contamination is made, it should not be hidden behind anonymity.  Blinding during an experiment is one thing but blinding in reporting results to protect the perpetrators is another.   Methods reported in this paper are impossible to replicate when information about the 44 products tested are blinded.  The criminality imputed by the authors of this report place a burden on the authors to reveal the specific products and submit the materials to prosecution.

It is disconcerting that the authors state: “There are currently no best practices in place for identifying the species of the various ingredients used in herbal products.”  In fact, many major and well known organizations have been addressing this for decades.  Consider the variety of materials on herbal Good Manufacturing Practices (GMP) provided by the British Herbal Medicine Association (BHMA, 1), US Pharmacopeial Convention (USP, 2), American Herbal Pharmacopoeia (AHP, 3), World Health Organization (WHO, 4), National Institute of Standards and Technology (NIST, 5).  When an author exaggerates about a potential problem then all methods and data are placed in doubt, and trust is lost in their hiding behind blinding the products tested.

Fillers ought not to be used in the same sentences as adulterants.  While fillers do deserve disclosure (something which the authors of this piece do not do for the products tested), as long as the fillers are the usual inert carbohydrate and mineral materials used to improve dissolution and absorption, then they do not arise to being clumped with adulterants.

All in all, it is difficult to judge from the paper and data released whether the authors of this report might be making exaggerations or a sober accounting about the products.


1.  ISBN-10: 0903032104


Competing interests

none (retired from US National Institutes of Health)


Does this finding undermine previous research?

Matthew Marturano   (2013-11-25 09:57)  Natural Solutions for Digestive Health email

It would appear to me that the prevalence of contamination and substitution of herbal products reported in this paper calls into question any previous research (both negative and positive) in which the investigators did not verify the identity of an herbal substance before administering it to the participants.

Perhaps the authors could comment on what kind of confounding impact these findings might have on the body of research on herbal products, in general. For example, negative studies on St. John's wort, echinacea, and saw palmetto, are well-known. What if there were a bias, particularly in larger studies, toward using more inexpensive products and therefore from manufacturers with less robust QA/QC procedures and personnel?

Competing interests

I am a naturopathic physician with a part-time private naturopathic practice, in which I sell dietary supplements, and a natural products industry recruitment service.


Named consumer products...??

Michael Czech   (2013-10-14 10:08)  Nonspecific

So which 2 products came out as clean? As a consumer, I would like to know which company I should be supporting and which ones I should be avoiding..... Thank you..

Competing interests

None declared


Missing list of companies products analysed

Pierre K McKenty   (2013-10-14 10:08)  home office email

As a consumer of such berbal based supplements, I am very concerned by the fact the products tested are not listed by companies and brand names.
A more public publication of this research would give consumers an opportunity to make better informed choices. Monitoring agencies - Health Canada and FDA - would have better supervising tools and recall protocoles, and product companies could better "defend" and quality control their products.
Has any of these companies had an opportunity to review and answer the questions raised by the assertions of this study ?

Competing interests



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