By Kaela Colwell
Global sales of herbal supplements have grown by roughly $40 billion over the last fifteen years—from close to $60 billion in 2000 to nearly $100 billion in 2015—and they are expected to continue to grow at a rate between three percent and twelve percent per year. Due in part to the prevalent assumption that “natural” means “harmless,” individuals view products derived from herbs as a safe way to improve overall health and well being, alleviate symptoms resulting from chronic diseases, and avoid the side effects associated with conventional medicines. Yet recent adverse event reports indicate that consumer confidence in the quality of herbal supplements may not be fully warranted—and recent scientific studies indicate that the natural environment may deserve much of the blame.
In addition to revealing potential side effects and interactions with orthodox drugs, tests on popular herbal products have uncovered the presence of heavy metals, pesticide residues, and other external toxins. While some of this contamination results from poor processing practices, much stems from the agricultural inputs involved in herb cultivation. Industrial emissions, toxic waste disposal, and the spraying of pesticides for agriculture and disease control impact the quality of the soil, water, and air used to grow herbal plants, which consequently affects the quality of the herbs themselves.
Moreover, industrialization and changing climate conditions have contributed to the endangerment or extinction of several herb species, which in turn has led some herb traders to source cheaper, “fake” herbs that are difficult to distinguish from their medicinal counterparts. It has also encouraged some manufacturers to produce pills, capsules, and other products completely deficient of the herbs listed on their labels.
Since most herbal products fit within the Food, Drug, and Cosmetic Act’s (FDCA) definition of “dietary supplement,” the U.S. Food and Drug Administration (FDA)—the primary agency responsible for ensuring herbal product safety and efficacy—has minimal authority to regulate such external quality issues. Per a 1994 amendment to the FDCA, products sold as dietary supplements must not contain adulterated ingredients or unapproved food additives, and since 2008, manufacturers must follow dietary supplement-specific “good manufacturing practices.” However, unlike new drugs, dietary supplements need not be tested or pre-approved by the FDA before they can be marketed. Furthermore, unlike new food ingredients, new dietary ingredients do not have to be Generally Recognized as Safe (GRAS) before they can be incorporated into products categorized as dietary supplements.
Intuitively, heavy metals and pesticide residues seem like they should be classified as adulterated ingredients or new ingredients, but they, like new dietary ingredients, are excluded from the FDCA’s definition of food additive and are therefore not subject to FDA premarket evaluation. Instead, the U.S. Environmental Protection Agency (EPA) sets tolerance levels for these contaminants, and the FDA is then responsible for enforcing them. Yet the FDA has been hesitant to enforce the EPA’s tolerance levels because the thresholds are determined for foods using the “intake method,” and consequently “cannot be strictly applied to dietary supplements.” Although any product containing the residue of a pesticide for which a tolerance level has not been set “is considered adulterated and its sale is prohibited,” many of these products continue to remain on the market due to lack of information regarding their content—the FDA has insufficient resources to support regular studies of herbal products, and it can only pursue action against products that research or adverse event reports indicate may pose “a significant or unreasonable risk of illness or injury.”
Though the EPA continues to address issues of industrial pollution, natural resource exploitation, and other factors affecting medicinal herb quality, its efforts are constrained by the fact that agricultural operations are largely exempt from regulation and that many medicinal herbs are grown and processed outside of the United States. Accordingly, the agency’s largest contribution to ensuring herbal product safety and efficacy has been through its roles in enforcing the Endangered Species Act and the Lacey Act, both of which generally prohibit the trafficking of threatened or endangered plant species.
As herbal supplement consumption continues to increase, the inadequacies of the U.S.’s current regulatory scheme will only become more problematic. Continued disconnect between the FDA’s post hoc efforts and the EPA’s indirect efforts to regulate herbal supplement quality will make necessary improvements to medicinal herb safety and efficacy difficult. Effective policy solutions will require greater appreciation for the interdependence between medicinal herb quality and the quality of the natural environment. The World Health Organization and countries such as China and the member states of the European Union have already developed guidelines and policies consistent with this concept. The U.S. should be next.
 See Junhua Zhang et al., Quality of Herbal Medicines: Challenges and Solutions, 20 Complementary Therapies in Medicine 100, 101 (2012) (discussing global usage of herbal medicines); Steven Daniels, Herbal Supplement Sales to Hit $93.15 billion by 2015: Report, NutraIngredients (Dec. 10, 2015) http://www.nutraingredients-usa.com/Markets/Herbal-supplement-sales-to-hit-93.15-billion-by-2015-Report.
 TC Clarke et al., Trends in the Use of Complementary Health Approaches Among Adults: United States, 2002–2012, 79 Nati’l Health Stat. Rep. 1 (2015).
 See, e.g., Zhang, supra note 2, at 100-04.
 See María R. Gomez et al., Determination of Heavy Metals for the Quality Control in Argentinian Herbal Medicines by ETAAS and ICP-OES, 45 Food & Chemical Toxicology 1060, 1061 (2007).
 The FDCA currently defines dietary supplement as “a product (other than tobacco) intended to supplement the diet that contains one or more of the following ingredients: a vitamin; a mineral; an herb or other botanical; an amino acid; a dietary substance for use by man to supplement the diet by increasing total dietary intake; or a concentrate, metabolite, constituent, extract, or combination of any ingredient described above.” 21 U.S.C. § 321(ff) (2015).
 V H Frankos et al., FDA Regulation of Dietary Supplements and Requirements Regarding Adverse Event Reporting, 87 Clinical Pharmacology & Therapeutics 239, 240 (2010).
 Id.; see also 21 C.F.R. § 111.1 (2015).
 Per the FDCA and the FDA’s implementing regulations, a food substance may be determined to be Generally Recognized as Safe “either through scientific procedures or, for a substance used in food before 1958, through experience based on common use in food.” Generally Recognized as Safe (GRAS), U.S. Food & Drug Admin., http://www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/default.htm (last updated June 4, 2015).
 See 21 U.S.C. § 321(s) (2015).
 Herbal Dietary Supplements: Examples of Deceptive or Questionable Marketing Practices and Potentially Dangerous Advice, U.S. Gov’t Accountability Office 6-7 (2010), http://www.gao.gov/assets/130/124769.pdf [hereinafter Herbal Dietary Supplements].
 Id.; see also Pesticide Q&A, U.S. Food & Drug Admin., http://www.fda.gov/Food/FoodborneIllnessContaminants/Pesticides/ucm114958.htm (last updated Nov. 2, 2015).
 FDA 101, supra note 72.