Herbal Supplements: Increasing Problems

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Barrie R. Cassileth, MS, PhD

Jyothi Gubili, MS

K. Simon Yeung, PharmD, MBA, LAc

The popular belief that herbs are safer than synthetic pharmaceuticals continues unabated. Sales of herbal products reached $6 billion in 2013.

—Jyothi Gubili, MS, K. Simon Yeung, PharmD, MBA, LAc, and Barrie R. Cassileth, MS, PhD

In Don Quixote, the 1605 Spanish literary masterpiece by Miguel Cervantes, “Balsam of Fierabras” is mentioned often as a therapeutic panacea. It calls for mixing rosemary, wine, oil, and salt. As the story goes, the knight relied heavily on this herbal preparation to relieve him of pain from the many beatings he was subjected to following his exploits.1

Since ancient times, herbs have been used as medicine in cultures around the world. Today, herbalists continue to prescribe herbal formulas to treat a range of ailments. The 1990s saw a major change in the way herbal medicines were consumed, as herbal remedies were marketed as supplements following the passage of the Dietary Supplement Health Education Act.

A Question of Quality

The major downside of the Dietary Supplement Health Education Act is that dietary supplements are not subjected to the same safety and effectiveness requirements as drugs are, by the U.S. Food and Drug Administration (FDA). With limited oversight, the quality of available products was found to vary substantially across manufacturers. Some contain too much or too little of the labeled ingredient. Others are manufactured under poorly controlled conditions. Although companies are required to follow good manufacturing practices, lack of strict regulation has resulted in the proliferation of unscrupulous practices, including false health claims.

Examples include reports on adulterated herbal products that have surfaced in the past 2 years. A 2013 study of 37 saw palmetto–containing supplements found that 6% contained species that cannot legally be sold as dietary supplements in the United States. The identity of an additional 9% of supplements remained inconclusive.2 A 2013 Canadian investigation of 44 herbal products sold by 12 companies revealed that the majority were of poor quality, including product substitution, contamination, and use of fillers.3

A recent case of questionable supplements was exposed by the New York Attorney General, which led to the issuance of cease-and-desist letters to four major retailers in the New York area, preventing them from selling those products.4 However, the validity of the DNA barcoding technique used in the investigations is being debated.5

Steps to Ensure Safety

The popular belief that herbs are safer than synthetic pharmaceuticals continues unabated. According to the most recent National Health Survey conducted in 2012, the most commonly used complementary approach was the use of natural products.6 Sales of herbal products reached $6 billion in 2013.7

What steps can consumers take to purchase products with some certainty that what’s on the label is indeed inside the bottle? A good way to ensure the quality of supplements is to purchase products with labels indicating they have been tested by either the U.S. Pharmacopoeia (USP) Convention Dietary Supplement Verification Program or These are two major independent groups that routinely evaluate products submitted by manufacturers to ensure that they meet the minimum quality standards.

A USP-verified product means it contains the listed ingredients at the strength indicated and that it has been screened for harmful contaminants. is a company that collects several brands of a product and independently tests, reviews, compares, and rates them. The company’s process also involves ascertaining that the product contains the listed ingredients and is not contaminated or adulterated. In addition to labels on dietary supplement packaging, provides detailed information about its findings in its paid-subscription offerings. However, neither USP nor evaluates the efficacy of the products or product-prescription drug interactions.

Stricter Regulation Needed

In 2010, the FDA established a system for regulators to track complaints about dietary supplements and to prevent products in question from being sold. Given the estimated 65,000 products currently available,3 such checks and balances will barely impact the status quo.

There is clearly an urgent need for stricter regulation of the dietary supplement industry. Had the rosemary used to concoct the Balsam of Fierabras been inauthentic, Don Quixote would not have been reinvigorated to continue his whimsical quests, depriving us of a great story. ■

Disclosure: Ms. Gubili, Dr. Yeung, and Dr. Cassileth reported no potential conflicts of interest.


1. López-Muñoz F, Alamo C, García-García P: Psychotropic drugs in the Cervantine texts. J R Soc Med 101:226-234, 2008.

2. Little DP, Jeanson ML: DNA barcode authentication of saw palmetto herbal dietary supplements. Sci Rep 3:3518, 2013.

3. Newmaster SG, Grguric M, Shanmughanandhan D, et al: DNA barcoding detects contamination and substitution in North American herbal products. BMC Med 11:222, 2013.

4. Press Release: A.G. Schneiderman asks major retailers to halt sales of certain herbal supplements as DNA tests fail to detect plant materials listed on majority of products tested. Press Release. Available at Accessed February 18, 2015.

5. Sarma N: DNA testing of herbal supplements—Does it work or doesn’t it? Available at Accessed February 18, 2015.

6. National Center for Complementary and Integrative Health: What complementary and integrative approaches do Americans use? Key findings from the 2012 National Health Interview Survey. Available at Accessed February 18, 2015.

7. American Botanical Council: Herbal dietary supplement retail sales up 7.9% in 2013. Available at Accessed February 18, 2015.


Guest Editor

Integrative Oncology is guest edited by Barrie R. Cassileth, MS, PhD, Chief of the Integrative Medicine Service and Laurance S. Rockefeller Chair in Integrative Medicine at Memorial Sloan Kettering Cancer Center, New York.

The Integrative Medicine Service at Memorial Sloan Kettering Cancer Center developed and maintains a free website—About Herbs (—that provides objective and unbiased information about herbs, vitamins, minerals, and other dietary supplements, and unproved anticancer treatments. Each of the close to 300 and growing number of entries offer health-care professional and patient versions, and entries are regularly updated with the latest research findings.
In addition, the About Herbs app, Memorial Sloan Kettering Cancer Center’s very first mobile application, can be downloaded at The app is compatible with iPad, iPhone, and iPod Touch devices.