Adulteration and Undeclared Drugs in Traditional Products
How some traditional and herbal products have been found to contain drugs or plants that are not on the label, what regulators and studies report, and how to protect yourself.
Content last updated . This page has not been medically reviewed.
Urgent first
If you took a product and feel seriously unwell, with trouble breathing, chest pain, fainting, bleeding or a seizure, call 911 in the United States. Poison Help is 1-800-222-1222. See poisoning: what to do first. Do not stop a prescribed medicine on your own because of this page.What adulteration means
Adulteration means a product contains something that is not declared on its label. It can be a prescription drug added to a product sold as natural, a different plant swapped in for the one named, or a banned substance. This is different from a product that is simply low quality or contains metals, which is covered in heavy metals in traditional medicines.Why does it matter? Hidden drugs act on the body even though no one expects them. They can cause side effects, interact with your prescriptions, or cause harm to people with certain conditions.
What research found
| Study | What it found | Limits |
|---|---|---|
| Systematic review of Chinese herbal medicines (2002) | 18 case reports, two case series and four analytical investigations; adulterants included corticosteroids, and in one Taiwan report 24% of samples contained at least one conventional drug. [5] | Old, and covers one region's products |
| FDA warnings on dietary supplements, 2007 to 2016 (2018) | 776 adulterated supplements identified; most were marketed for sexual enhancement, weight loss or muscle building. [6] | Mostly general supplements, not traditional medicine specifically |
| 26 traditional Chinese medicine products (2015) | 50% contained DNA of undeclared plant or animal taxa, and 50% contained an undeclared drug such as warfarin or dexamethasone. [7] | Small sample; not all products |
The 2018 analysis also noted that 19 of 28 products named in repeated warnings were reported to contain new unapproved ingredients the second or third time, so a product can change after a warning. [6] In the aristolochic acid kidney disease reviews, herb substitution was a documented route to exposure. [8]
These findings describe products that were tested. They do not mean every product from a tradition is adulterated, and they say nothing against the tradition's practitioners as a group.
What you can do
- Search the FDA's health fraud product database, remembering that it covers only a fraction of products. [1]
- Show the product to a pharmacist or clinician, and say why you take it.
- Report suspected problems: reporting a problem with a traditional product or practitioner.
Related pages
Traditional herbs and prescription medicines, unsafe products and warnings, and the safety overview.Frequently asked questions
What is a hidden or undeclared drug?
It is a drug ingredient that is not listed on the label, often a prescription drug or banned substance. [1]
Are traditional Chinese medicines often adulterated?
Some tested products were. One small study found undeclared drugs in half of 26 products. [7] That cannot be generalized to all products.
Does a "natural" label mean no drugs are inside?
No. The FDA describes contaminated products falsely advertised as supplements or all-natural treatments. [2]
If a product is not on the FDA list, is it safe?
Not necessarily. The FDA says the list covers only a small fraction of contaminated products. [1]
Who can help me check a product?
A pharmacist or your clinician. NCCIH advises that supplements can contain ingredients not on the label. [4]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
What regulators say
NCCIH likewise warns that some products sold as dietary supplements, mainly for weight loss, sexual enhancement and bodybuilding, may contain prescription drugs not allowed in supplements or other ingredients not on the label. [4]
Warning signs
- Claims of fast, dramatic results for pain, weight, sexual function or blood sugar.
- Labels that say "all natural" while promising effects like a prescription drug.
- Products sold mainly online, on social media or by unknown sellers, and imported products with no ingredient list in your language.
- A product that works suspiciously well, or causes effects you would expect from a steroid or similar drug, such as weight gain or high blood sugar. The FDA lists sudden weight gain, bleeding, higher blood sugar and liver toxicity among effects reported with some contaminated products. [1]
References
- US Food and Drug Administration. Avoiding Products Contaminated with Hidden Ingredients. Read 2026-10-22.
- US Food and Drug Administration. Pain and Arthritis Products Containing Hidden Ingredients. Read 2026-10-22.
- US Food and Drug Administration. Questions and Answers on Dietary Supplements. Read 2026-10-22.
- National Center for Complementary and Integrative Health. Using Dietary Supplements Wisely. Read 2026-10-22.
- Ernst E. Adulteration of Chinese herbal medicines with synthetic drugs: a systematic review. Journal of Internal Medicine 2002. Read 2026-10-22.
- Tucker J and others. Unapproved pharmaceutical ingredients included in dietary supplements associated with US Food and Drug Administration warnings. JAMA Network Open 2018. Read 2026-10-22.
- Coghlan ML and others. Combined DNA, toxicological and heavy metal analyses provides an auditing toolkit to improve pharmacovigilance of traditional Chinese medicine. Scientific Reports 2015. Read 2026-10-22.
- Debelle FD and others. Aristolochic acid nephropathy: a worldwide problem. Kidney International 2008. Read 2026-10-22.