Traditional Remedies With Documented Harm: Examples and Warning Signs
Documented cases of harm from traditional and herbal remedies, from kidney and liver injury to lead poisoning and banned ingredients, with warning signs and when to get care.
Content last updated . This page has not been medically reviewed.
Urgent first
Call 911 in the United States for trouble breathing, chest pain, fainting, a seizure, heavy bleeding, and for a child who may have swallowed a product and is very drowsy. Poison Help is 1-800-222-1222. See poisoning: what to do first. Do not stop a prescribed medicine on your own; the NHS advises talking to a doctor first. [1]Are traditional remedies safe?
Some are used for long periods with few reported problems, and some have caused serious harm. Long use is not proof of safety. The Korean liver injury review began from the observation that herbal drugs are generally regarded as safe because of extensive clinical use, then identified 97 cases of herb-induced liver injury. [2] The examples below are documented cases. They are not a verdict on any tradition, and most involve particular herbs, products or contamination.Documented examples
| Example | What was documented | Strength of evidence |
|---|---|---|
| Aristolochic acid in herbal products | A Belgian cohort of more than 100 patients developed progressive kidney disease after slimming pills containing a Chinese herb, Aristolochia fangchi; the disease is frequently associated with urinary tract cancers. [3] | Well documented. Cases have declined where such herbs were restricted but are still reported sporadically, and there is no effective treatment to reverse the kidney damage. [4] |
| Herb substitution | In Asia, the complexity of the pharmacopoeia raises risk because herbs containing aristolochic acid are frequently substituted for other botanicals. [3] | Review article |
| Herb-induced liver injury | 97 cases in Korea from 31 reports; the most frequent causes were two herbs. [2] | Case reports and series |
| Kava | Various kava products have been linked to rare cases of liver injury, some serious or even fatal. [5] | Case reports; cause still debated |
| Ephedra | Banned in dietary supplements in the United States in 2004; linked to high blood pressure, heart attack, seizure, stroke and psychosis. [6] | Documented harm |
| Lead-based folk remedies | Mexican azarcon, greta and albayalde, used for empacho, were very high in lead. [7] | Product analysis |
| Metal-containing Ayurvedic products | Some tested products contained lead, mercury or arsenic. [8] | Product testing |
| Hidden drugs | The FDA reports products with undeclared prescription drugs causing serious effects, including liver toxicity and death. [9] | Regulator notices |
"Strength of evidence" here means how solid the documentation of harm is. Case reports can show that harm occurred but not how often.
Why harm happens
A review of herbal nephrotoxicity lists several contributors: the herb's own toxicity, incorrect processing or storage, adulteration, metal contamination, incorrect dosing and interactions with medicines. [10] The same review says harm can be overlooked by physicians and patients because people believe herbal medicines are innocuous. [10] For details see heavy metals, hidden drugs and medicine interactions.Warning signs
- Any new or unexplained symptoms after starting a product. Report them; this is not a diagnosis.
- A product that promises quick results, works like a prescription drug, or has no clear ingredient list.
- A practitioner who tells you to stop a prescribed medicine or says your diagnosis is wrong without examining you.
If you have symptoms, stop taking the product and contact a clinician, bringing the product with you. Clinicians are advised to consider herbal medicine use in people with unexplained acute kidney injury or progressive chronic kidney disease, so tell them. [10]
What this page does not say
It does not say that all herbs are dangerous, that conventional medicine has no harms, or that a tradition is unsafe as a whole. The question for any product is the same: what is in it, who made it, what is the evidence it helps, and what is the evidence it harms.Related pages
Reporting a problem with a traditional product or practitioner, African herbs and HIV claims, unsafe products and warnings, and the safety overview.Frequently asked questions
Are traditional remedies safe?
It depends on the product. Some have caused serious harm, such as kidney injury linked to aristolochic acid. [3]
Can herbs damage the liver or kidneys?
Yes. Reviews document herb-induced liver injury and kidney damage from some herbs. [2][10]
Is a banned herb still sold?
Herbs containing aristolochic acid are no longer permitted in many countries, but a 2008 review found they were still sold online. [3]
Does a long history of use prove a remedy is safe?
No. Cases of harm have occurred with long-used herbs. [2]
What should I do if I think a remedy harmed me?
Stop the product, see a clinician with the product, and report it. [10]
References
- NHS. Herbal medicines. Read 2026-10-22.
- Lee WJ and others. Systematic review on herb-induced liver injury in Korea. Food and Chemical Toxicology 2015. Read 2026-10-22.
- Debelle FD and others. Aristolochic acid nephropathy: a worldwide problem. Kidney International 2008. Read 2026-10-22.
- Zhou Q and others. Overview of aristolochic acid nephropathy: an update. Kidney Research and Clinical Practice 2023. Read 2026-10-22.
- National Center for Complementary and Integrative Health. Kava. Read 2026-10-22.
- National Center for Complementary and Integrative Health. Ephedra. Read 2026-10-22.
- Baer RD and others. Toxic Mexican folk remedies for the treatment of empacho: the case of azarcon, greta, and albayalde. Journal of Ethnopharmacology 1988. Read 2026-10-22.
- Saper RB and others. Lead, mercury, and arsenic in US- and Indian-manufactured Ayurvedic medicines sold via the Internet. JAMA 2008. Read 2026-10-22.
- US Food and Drug Administration. Avoiding Products Contaminated with Hidden Ingredients. Read 2026-10-22.
- Yang B and others. Nephrotoxicity and Chinese herbal medicine. Clinical Journal of the American Society of Nephrology 2018. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.