Undeclared Drugs in Chinese Patent Medicines
Some products sold as Chinese herbal or patent medicines have been found by regulators and hospital labs to contain prescription drugs not on the label; what was found and how to lower the risk.
Content last updated . This page has not been medically reviewed.
If you think you have taken one of these products
For severe symptoms in the United States, call 911. For poisoning questions, Poison Help is 1-800-222-1222 (other countries: poison help by country). If a product turns out to contain a steroid, do not simply stop it on your own. The FDA tells people to talk to a health care professional about stopping safely, because abruptly stopping a corticosteroid can cause withdrawal symptoms. [1] Bring the package to your clinician or pharmacist.What "undeclared drug" means
Most Chinese herbal products are what their label says. A small, important group is not. An undeclared (or "adulterated") product contains a medicine that is not listed on the label, usually a prescription drug that works quickly, so the product seems to "work." The FDA describes these hidden ingredients as often being prescription drug ingredients, banned substances or harmful chemicals. [2] This is a problem of illegal products, not of traditional Chinese medicine theory. It is covered here because people who buy "natural" products for pain, skin conditions, diabetes or weight cannot tell by looking.What the numbers can and cannot tell you
The Hong Kong figures come from cases sent to a referral laboratory, so they show what harm is possible, not how common adulteration is across all products. Even so, 65.1% of those patients had adverse effects tied to the products, including 14 severe and two fatal cases; psychosis, steroid excess (Cushing syndrome) and low blood sugar were the most common. [7] The reported sources included drug stores, the internet and Chinese medicine practitioners, so a shop or a clinic is not a guarantee. [7]A separate series of 27 cases involved herbal products sold for diabetes. Hypoglycemia (low blood sugar) was the most common harm, followed by lactic acidosis. [8] This matters for anyone taking diabetes medicine as well, because a hidden pill can be a second dose of the same kind of drug. See Chinese herbs with diabetes, blood pressure and heart medicines.
Why hidden drugs are dangerous
- You cannot know the dose or that you are taking a drug.
- Steroids can weaken defenses against infection, raise blood sugar and cause muscle and mood problems. [1]
- The hidden drug can combine badly with your own medicines. [3]
- Signs a hidden steroid may be involved can include a round face and upper-body weight gain (Cushing's syndrome), as in the Singapore case. [5] Only a clinician can judge this; do not self-diagnose.
Evidence labels
| Question | What sources found | Label |
|---|---|---|
| Have products sold as Chinese herbal medicines contained undeclared drugs? | Yes, in FDA, Singapore and Hong Kong findings | Established |
| Are most traditional formulas from regulated makers adulterated? | Not measured by these sources | Insufficient evidence |
| Does a product's "all natural" claim show it is free of drugs? | FDA says these products are often represented as "all natural" [4] | Marketing claim |
Frequently asked questions
Which drugs have been found in these products?
Corticosteroids such as dexamethasone, antihistamines, diuretics, anti-inflammatory painkillers, appetite suppressants and diabetes pills have all been reported. [7][4]
Does this mean Chinese herbal medicine is unsafe?
No single conclusion fits all products. NCCIH notes that some Chinese herbal products have been contaminated with drugs, heavy metals or wrong herbs, which is why sourcing and clinician review matter. [9]
Can I tell by taste, smell or appearance?
No. A hidden drug does not change how a pill looks, and the FDA states it cannot test every product on the market. [3]
What should I do if I have used a product the FDA named?
Stop and contact a health care professional, and do not stop a steroid abruptly without advice. [1] Keep the package and tell your pharmacist.
Does buying from a practitioner or shop make it safe?
Not by itself. In the Hong Kong series the reported sources included drug stores, the internet and Chinese medicine practitioners. [7]
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 found
- United States (FDA). The FDA has issued public notices naming products promoted for joint pain, skin conditions or pain. Laboratory analysis found dexamethasone (a corticosteroid) and chlorpheniramine (an antihistamine) in one skin-condition pill [3], and dexamethasone, chlorpheniramine and furosemide in two products promoted for pain [1][4]. Furosemide is a prescription diuretic. [4] The FDA says it cannot test and identify every product sold as a dietary supplement. [3]
- Singapore (Health Sciences Authority). In 2016 the authority warned about three products with undeclared dexamethasone or diclofenac. They had no ingredient list on the label. One patient in his 40s was hospitalized with Cushing's syndrome after using one of them. [5] Over 2010 to 2016, the most common adulterants in reports to the authority were dexamethasone, chlorpheniramine and piroxicam. [6]
- Hong Kong (hospital toxicology laboratory). A review of confirmed cases from 2005 to 2015 found 404 cases involving 487 adulterated products and 1,234 adulterants. [7] The most common categories were anti-inflammatory painkillers, appetite suppressants, corticosteroids, diuretics and laxatives, and diabetes pills. [7]
Lowering your risk
- Be most careful with products promoted for pain, arthritis, skin conditions, weight loss, sexual enhancement or diabetes, or described as working fast or "without side effects."
- Be wary of products with no ingredient list, a label that is not in a language you read, or imports ordered online; the FDA notes contaminated products appear in popular online marketplaces. [2] Read how labels work in reading a Chinese patent medicine label.
- An FDA list is not a safety check: if a product is not on the FDA's list, that does not mean it is safe. [2]
- Tell every clinician, including your pharmacist, what you take. [9]
- Report problems to the FDA's MedWatch program in the US. [3] More on reporting: side effects and reporting.
For other quality problems (heavy metals, wrong plant) see Chinese herbal products: quality, contamination and interactions and heavy metals in Chinese medicines. For how oversight differs by country: how Chinese herbal products are regulated.
References
- FDA, Nhan Sam Tuyet Lien Truy Phong Hoan may be harmful due to hidden drug ingredients (US, notice current as of 11-01-2024). Read 2026-10-22.
- FDA, Avoiding products contaminated with hidden ingredients (US). Read 2026-10-22.
- FDA, Vail-Bon Jie Yang Wan contains hidden drug ingredients (US, 7-10-2024). Read 2026-10-22.
- FDA, Public Notification: Jianbu Huqian Wan contains hidden drug ingredients (US, 2015). Read 2026-10-22.
- Health Sciences Authority (Singapore), HSA alerts public to three health products found to contain undeclared Western medicinal ingredients (25 January 2016). Read 2026-10-22.
- Xu Y et al. Retrospective study of reported adverse events due to complementary health products in Singapore from 2010 to 2016. Front Med 2018. Read 2026-10-22.
- Ching CK et al. Adulteration of proprietary Chinese medicines and health products with undeclared drugs: experience of a tertiary toxicology laboratory in Hong Kong. Br J Clin Pharmacol 2018. Read 2026-10-22.
- Ching CK et al. Adulteration of herbal antidiabetic products with undeclared pharmaceuticals: a case series in Hong Kong. Br J Clin Pharmacol 2012. Read 2026-10-22.
- NCCIH, Traditional Chinese Medicine: What You Need To Know (US). Read 2026-10-22.