Confessions of a Quackbuster

This blog deals with healthcare consumer protection, and is therefore about quackery, healthfraud, chiropractic, and other forms of so-Called "Alternative" Medicine (sCAM).

Wednesday, November 09, 2005

Lack of herbal supplement characterization in published randomized controlled trials

The American Journal of Medicine
Volume 118, Issue 10 , October 2005, Pages 1087-1093

Lack of herbal supplement characterization in published randomized controlled trials

Peter M. Wolsko MD, MPHa, , , David K. Solondz BSEb, Russell S. Phillips MDc, Steven C. Schachter MDd, e and David M. Eisenberg MDe

* Kaiser Permanente Medical Group, Denver, Colo
* Tufts University School of Medicine
* Division of General Medicine and Primary Care at Beth Israel Deaconess Medical Center
* Office of Clinical Trials and Research, Beth Israel Deaconess Medical Center
* Division for Research and Education in Complementary and Integrative Medical Therapies at Harvard Medical School, Boston, Mass

Received 2 November 2004; revised 31 January 2005; accepted 31 January 2005. Available online 27 September 2005.


Herbal supplements in the United States and abroad have poor quality control and high content variability. We assessed the extent to which recently published randomized controlled trials of herbal supplements characterized and verified the content of the supplement under study.

We identified all MEDLINE-indexed English language randomized controlled trials evaluating single-herb preparations of echinacea, garlic, ginkgo, saw palmetto, or St. John’s wort that were published between January 1, 2000, and February 9, 2004. From each article we extracted information characterizing the herbal supplement studied.

Of 81 randomized controlled trials meeting inclusion criteria, 12 (15%) reported performing tests to quantify actual contents, and 3 (4%) provided adequate data to compare actual with expected content values of at least one chemical constituent. In those 3 studies, actual content varied between 80% and 113% of expected values. Studies of higher overall quality (Jadad score ≥3) performed testing somewhat less frequently (5/54; 9%) than those with lower Jadad scores (7/27; 26%) (P = .09).

Documented characterization of herbal supplements in published randomized controlled trials is inadequate. Investigators may be unaware of the extent to which herbal quality-control issues may detract from the value of otherwise well-designed clinical trials. The scientific and clinical utility of future herbal randomized controlled trials would be enhanced if authors provided evidence that the herbal products studied were of high quality.

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