Adulteration, Substitution and Mislabeling of Herbal Products
What DNA-based and chemical testing studies found when herbal products were checked against their labels, including substitutes, fillers and missing plants, and what these studies can and cannot show.
Content last updated . This page has not been medically reviewed.
If someone feels unwell after a herbal product, call 911 for collapse, seizure, trouble breathing or swelling of the face or throat, or Poison Help at 1-800-222-1222 (US). See Poisoning: What to Do First.
When researchers tested herbal products against their labels, they often found plants that were not listed, and sometimes did not find the plant that was. The size of the problem differs a lot between studies, products and countries. This page reports what the studies found. It does not name brands and it does not say any single product is affected.
Words used in this topic
- Adulteration: a herbal product contains undeclared contaminant, substitute or filler species, or none of the labeled species. Researchers say this may be accidental or intentional and economically motivated. [1]
- Substitution: one plant is used in place of another, for example a different species of the same genus. [2]
- Mislabeling: the label does not match what is inside. In the studies below, researchers report "fidelity", which compares the label ingredients with what DNA testing detected. [3]
What testing found
| Study | Products | What it found | Strength and limits |
|---|---|---|---|
| Ichim 2019 (review of DNA studies) | 5,957 commercial herbal products from 37 countries | 27% were adulterated when tested against labeled species; the share varied by region, from 23% in Asia to 79% in Australia. [1] | Combines studies with different methods and samples; a review, not a market audit. |
| Raclariu 2017 | 78 products labeled as containing Hypericum perforatum L. (St. John's wort) | The plant was detected in 68% by DNA testing, and every product showed a mismatch between listed and detected species. [2] | One plant; a laboratory study of purchased products. |
| Raclariu 2018 | 53 Echinacea (genus) products marketed in Europe | Echinacea was detected in 34 of 38 retained products (89%); label-to-DNA fidelity was only 43%. [4] | Genus-level only; the method could not tell Echinacea species apart. |
| Seethapathy 2019 | 79 Ayurvedic products bought in Europe | Fidelity was 67% for single-ingredient and 21% for multi-ingredient products; eight of 27 multi-ingredient products contained none of the listed species. [3] | Authors say DNA methods still need standard protocols. |
| Coghlan 2015 | 26 traditional Chinese medicines | 50% contained DNA of undeclared plant or animal taxa, including an endangered species. [5] | Small sample; DNA does not show the amount. |
| NCCIH | Black cohosh (Actaea racemosa L.) products | Some commercial products were found to contain the wrong herb or mixtures not listed on the label. [6] | Summary statement; no sample size on that page. |
Percentages come from different groups of products. They cannot be added up or compared across plants. We found no source giving the share of all herbal products on a given country's market, so Proper evidence not found for that; we searched PubMed, Europe PMC and NCCIH.
Why it matters
- Safety. NCCIH says manufacturing errors in which one herb is mistakenly replaced with another have resulted in serious complications in Chinese herbal products. [7] See Banned and Restricted Ingredients and Aristolochic Acid and Herbal Nephropathy.
- Research. A study of one product does not transfer to a different plant or preparation. If a product holds a different species, research on the labeled plant may not apply.
- Conservation. Researchers reported threatened species detected in some products, which raises concern about illegal plant trade. [3] A review notes that, in India, of about 8,000 wild-harvested medicinal plant species, about 960 are in active trade. [8]
- Medicines. Hidden drugs are a different problem, covered in Hidden Drugs in Supplements.
What DNA testing can and cannot show
The studies used DNA methods that look for which plant species are present. One study found that chemical tests (TLC and HPLC-MS) could not unambiguously identify Hypericum perforatum, but are accurate for the target compounds, while DNA testing detected other species. [2] Another found chemical profiling detects target compounds but not other species in the product. [4] In short, the methods answer different questions, and no one test is enough.
A well-known 2013 DNA study of North American herbal products is marked as a retracted article in PubMed. [9] We do not use its results.
What a reader can do
- Prefer products with a clear scientific name and plant part on the label, and read Latin Names, Plant Parts and Extract Ratios.
- Learn what testing seals show: Third-Party Testing and Certifications.
- Tell a pharmacist or clinician about every herbal product, especially if you take a prescribed medicine, are pregnant or breastfeeding, or are preparing for surgery. Say "tell the surgical and anesthesia team" before any procedure.
- Report problems: Side Effects, Allergic Reactions and Reporting.
For single plants, see St. John's Wort, Black Cohosh and St. John's Wort Interactions.
Frequently asked questions
What is the difference between adulteration and substitution?
Adulteration is the wider term: undeclared contaminant, substitute or filler species, or none of the labeled species. [1] Substitution means one species is used in place of another.
Does DNA testing prove a product is unsafe?
No. It shows which plant DNA was found, compared with the label. It does not by itself show harm. One study says low fidelity raises concerns about the reliability of the products. [3]
Are Ayurvedic and Chinese products more affected than others?
The studies we read tested different products, so they cannot be compared fairly. Problems were also found in St. John's wort and Echinacea products. [2][4]
Does a Latin name on the label guarantee the right plant?
Not by itself. In the Hypericum study, products showed species mismatches with their labels. [2]
Why does the same plant sometimes get replaced?
The sources suggest causes such as limited supply of raw material from wild plants and economic motivation. [3][1]
References
- Ichim MC. The DNA-Based Authentication of Commercial Herbal Products Reveals Their Globally Widespread Adulteration. Front Pharmacol. 2019. Read 2026-10-22.
- Raclariu AC, Paltinean R, Vlase L, et al. Comparative authentication of Hypericum perforatum herbal products using DNA metabarcoding, TLC and HPLC-MS. Sci Rep. 2017. Read 2026-10-22.
- Seethapathy GS, Raclariu-Manolica AC, Anmarkrud JA, Wangensteen H, de Boer HJ. DNA Metabarcoding Authentication of Ayurvedic Herbal Products on the European Market Raises Concerns of Quality and Fidelity. Front Plant Sci. 2019. Read 2026-10-22.
- Raclariu AC, Tebrencu CE, Ichim MC, Ciuperca OT, Brysting AK, de Boer H. What's in the box? Authentication of Echinacea herbal products using DNA metabarcoding and HPTLC. Phytomedicine. 2018. Read 2026-10-22.
- Coghlan ML, Maker G, Crighton E, et al. Combined DNA, toxicological and heavy metal analyses provides an auditing toolkit to improve pharmacovigilance of traditional Chinese medicine (TCM). Sci Rep. 2015;5:17475. Read 2026-10-22.
- National Center for Complementary and Integrative Health (NCCIH). Black Cohosh. Read 2026-10-22.
- National Center for Complementary and Integrative Health (NCCIH). Traditional Chinese Medicine: What You Need To Know. Read 2026-10-22.
- Species Adulteration in the Herbal Trade: Causes, Consequences and Mitigation. Drug Saf. 2017. Read 2026-10-22.
- Newmaster SG, et al. DNA barcoding detects contamination and substitution in North American herbal products. BMC Med. 2013;11:222 (PubMed record marked as a retracted article; not used for any finding). Read 2026-10-22.