Lead, mold and germs can hitch a ride in herbal products

Key takeaways

• In a 2008 JAMA study of Ayurvedic products bought online, 20.7% contained detectable lead, mercury or arsenic, and U.S.-made products were as likely to test positive as Indian-made ones¹.
• Some metals are in the recipe on purpose: rasa shastra medicines are deliberately made with metals and minerals, and they were more than twice as likely to contain toxic metals¹³.
• In 2018, the CDC linked Salmonella in kratom, a plant product most often used as a powder, to 199 illnesses in 41 states, with 50 people hospitalized¹².
• Herbs can pick up aflatoxin, a cancer-causing mold toxin, during drying; surveys from eight countries found it in 18% to 94% of herb samples¹⁰.
• Lead poisoning often causes no symptoms at first, and the FDA says these remedies usually don’t list the metals they contain, so ask your clinician about a blood lead test if you’ve used one⁴⁶⁷.

In early 2015, a 64-year-old Wisconsin woman started taking two Ayurvedic medicines she had bought online⁵. Both were made in India. Over several weeks she grew more tired and short of breath, until she ended up at the hospital⁵.

Her blood held 85.8 micrograms of lead per deciliter, the standard unit for blood lead⁵. A typical U.S. adult has less than 1⁷. She was also badly anemic, meaning her blood was short of the red cells that carry oxygen⁵.

Health officials tested her tablets. One product, Mahayogaraj Guggulu, was 4.9% lead by weight, and it also contained arsenic and thallium⁵. Once she quit the remedies, doctors gave her an oral drug that pulls lead out of the body. A month into that treatment, she said her symptoms had eased⁵.

Stories like hers are uncommon, but they aren’t random. Herbs grow in soil, dry in open air, sit in warehouses and cross oceans. At each step, something unwanted can get in. In a few traditional recipes, metals are added on purpose.

This guide follows an herb from field to shelf and shows where contamination happens. It won’t ask you to give up herbs or their traditions. It will help you shop like an insider.

Contamination can enter at five points between the field and your shelf

Each link in an herb’s supply chain carries its own risk:

1. The field. Pesticides can be sprayed on the crop or arrive from far away, even on organic and wild plants⁸.
2. The harvest. Weeds picked along with the crop can add their own plant toxins. Our herbal tea guide covers the best-known example, pyrrolizidine alkaloids.
3. Drying. Herbs dried on bare ground can grow molds that leave toxins behind¹⁰.
4. Processing. Raw plant powders can carry germs such as Salmonella¹².
5. The recipe. Some traditional formulas include metals or minerals as ingredients³⁶.

No single country owns these problems. Since 2016, the FDA has placed supplement makers in Canada, Belgium, Australia, Brazil and China, including a maker of Chinese herbal teapills, on an import alert that lets it detain their products for falling short of U.S. manufacturing rules¹⁵.

One in five Ayurvedic products bought online held toxic metals

Dr. Robert Saper and colleagues at Boston University wanted to know what online shoppers were getting. Their 2005 web search turned up 673 Ayurvedic products². The team drew 230 at random, placed orders, and ran metal tests on the 193 that showed up¹².

JAMA published the results in 2008. About one product in five, 20.7%, held detectable lead, mercury or arsenic¹. Products made in the United States (21.7%) fared no better than those made in India (19.5%)¹. Nearly all the positives, 95%, came from U.S. websites².

Labels on three of every four metal-positive products advertised Good Manufacturing Practices². And every metal-positive product broke at least one standard for how much toxic metal a person can safely take in each day¹.

The biggest factor was the type of remedy. Ayurveda is a system of medicine that began in India and has been practiced for millennia³⁶. Within it, a branch called rasa shastra deliberately includes metals, minerals or gems, prepared as compounds called bhasmas³.

In Saper’s study, 40.6% of rasa shastra products contained detectable metals, compared with 17.1% of other Ayurvedic products¹. So the metal in many of these remedies isn’t a stray speck of dirt. It’s part of the formula, and modern testing measures it as a toxic dose.

That doesn’t describe Ayurveda as a whole. The CDC points out that not all Ayurvedic medicines contain metals on purpose³. Still, about one in six products from outside rasa shastra tested positive too¹.

The researchers’ fix was a federal one: enforced daily caps on toxic metals for every supplement, with makers proving compliance through outside labs².

CDC case reports show who gets hurt

Case reports can’t tell you how common a harm is, but they show what it looks like.

• Five states, 2000 to 2003. The CDC described 12 adults with lead poisoning linked to Ayurvedic remedies⁴. A California woman had taken nine remedies prescribed to boost fertility. One pill was 7.39% lead, and her blood lead reached 112 micrograms per deciliter⁴.
• New York city, 2011 to 2012. Six pregnant women had blood lead levels of 16 to 64 after using Ayurvedic medicines made in India³. All six had used rasa shastra products, and none had symptoms; routine prenatal screening caught them³. One baby’s blood lead was 23 at three days old³.
• California. State health officials linked lead poisoning in several infants to Balguti Kesaria, a tonic pill for babies bought in India that tested at 3,700 to 4,000 parts per million of lead⁷. The FDA has warned about it as well⁷.

The problem hasn’t gone away. In a warning updated in December 2025, the FDA described a report of a patient with extremely high blood lead⁶. Its lab then tested Rheumacare Ayurvedic Proprietary Medicine, bought from the website NavaFresh.com, and found high levels of lead and mercury, plus arsenic, strychnine and brucine⁶. The FDA told consumers to throw it away⁶.

Notice who keeps appearing: people seeking help with fertility, pregnancy, arthritis or diabetes³⁴. Several of these remedies were ordered online or came from India⁴⁵⁷. And the FDA warns that such products usually aren’t labeled as containing lead, mercury or arsenic⁶.

Pregnancy raises the stakes. The CDC warns that fetuses face added risk, and the FDA adds that metals can pass into breast milk⁴⁶.

Pesticide rules were written for crops, not for most herbs

Pesticide residues are the quiet contaminant, and the rules for them are tangled.

The U.S. Pharmacopeia (USP), a nonprofit that writes quality standards for medicines and supplements, sets limits for 70 pesticides in botanical ingredients⁸. For herbs sold as dietary supplements, though, the federal benchmark is the Environmental Protection Agency’s list of allowed residues, set crop by crop⁸.

This is the catch. Most of the more than 2,000 plants used in supplements have no EPA residue limit at all⁸. Technically, that means any detectable residue counts as a violation.

Robin Marles, then chair of USP’s botanical expert committee, gave an example. A chamomile shipment was held over 30 parts per billion of piperonyl butoxide, a pesticide residue⁸. The EPA allows 8 parts per million of that chemical on blueberries and cherries, more than 250 times as much⁸.

The point isn’t that the chamomile was dangerous. It’s that U.S. pesticide rules weren’t designed with herbs in mind, so they can be strict in odd places and silent in others.

Even plants that were never sprayed aren’t immune. Marles flagged a growing number of detections in certified organic and wild-collected herbs, traced to sources with no single point of origin⁸. Some pesticides travel so far through the atmosphere that they show up in Arctic ice⁸. An organic or wildcrafted label can’t promise zero.

What do surveys find? A 2022 study tested 1,125 samples of five Indian herbal ingredients that together make up 38% of India’s herbal export volume⁹. About 14.7% of raw herb samples and 5.9% of alcohol extracts exceeded European Union residue limits⁹.

Water extracts had no detectable residues⁹. The authors judged the health risk low in most cases and suggested that higher default limits might be possible⁹. The study came from a pharmacy college in Manipal, India; one author is listed at a private company, Herb Artizan⁹.

Molds and germs come from the drying shed and the factory floor

Molds thrive when drying goes wrong. Two species, Aspergillus flavus and Aspergillus parasiticus, make aflatoxins, which the World Health Organization’s cancer agency classifies as known human carcinogens¹⁰.

A 2022 review in Frontiers in Nutrition, summarized in a 2023 editorial, gathered aflatoxin surveys of herbs from eight countries¹⁰. Contamination rates ranged from 18% of samples in Thailand to 69% in Kenya and 94% in a small South African sample¹⁰. The editorial’s authors pointed to a likely culprit: herbs laid out to dry on the ground in open air¹⁰.

A 2025 review in the journal Toxins traced how aflatoxin and a second mold toxin, ochratoxin A, get into jujube fruit, lotus seed and licorice root¹¹. The fungus mattered, and so did the plant’s natural defenses, chemistry and stage of maturity¹¹.

Germs are the faster threat. In 2018, the CDC traced a Salmonella outbreak to kratom, a plant product sold as powder, capsules and tea¹². It sickened 199 people in 41 states and put 50 in the hospital; no one died¹².

Powder was the form patients mentioned most often¹². Investigators never found a single common source, and several companies recalled products¹². Kratom raises other safety questions beyond this outbreak, which our article on hidden drugs in herbal products takes up.

Salmonella usually brings diarrhea, fever and stomach cramps 12 to 72 hours after exposure, lasting four to seven days¹³. Children under 5, adults over 65 and people with weakened immune systems are most likely to get seriously ill¹³.

The rules ask makers to limit contaminants but rarely set the number

The FDA’s manufacturing rule for dietary supplements, finalized in 2007, defines quality partly as meeting the company’s own specifications for purity, including limits on contaminants¹⁵. When a foreign factory falls short, the FDA can hold that firm’s products at the border; the import alert was last updated in September 2026¹⁵.

For Ayurvedic products with metals, the FDA says it tests suspect products, recommends recalls, sends warning letters and adds companies to import alerts to keep their goods out⁶.

The rule leaves the numbers to each company. When it was new, Saper’s team noted that neither U.S. nor Indian rules capped toxic metal levels or daily doses in supplements².

The closest thing to a national yardstick comes from USP. An earlier edition of its chapter on metals in supplements, posted on a third-party site, sets daily limits of 5 micrograms for lead and cadmium and 15 for inorganic arsenic and total mercury¹⁴. Those limits bind only products labeled as meeting USP standards¹⁴.

Compare that with the extremes. One California patient taking three fertility remedies was swallowing about 65,000 micrograms of lead a day, which the state health department put at 5,200 times the recommended adult maximum⁷.

Lower your contamination risk: a buyer’s guide

Many people choose herbs because they want something purer than a factory-made pill. That instinct is worth keeping. But purity belongs to a specific batch from a specific supply chain, not to a plant or a tradition. The cases in this guide trace to particular products and shortcuts, not to Ayurveda or Chinese medicine as a whole.

Product type	Main risk	What to look for	Who tests
Traditional formulas listing metals, minerals, “bhasma” or “rasa”	Lead, mercury, arsenic13	Skip them, especially in pregnancy, while trying to conceive and for children	No FDA review before sale; health departments test after poisonings7
Remedies bought abroad, online or by mail	Metals56	A U.S. contact address, lot number and batch test results	The FDA can detain products from firms on its import alerts615
Dried roots, fruits and seeds, such as licorice root or jujube	Mold toxins1011	No musty smell, clumping or visible mold; aflatoxin testing by batch	The maker, under its own specifications15
Raw plant powders	Salmonella and other germs12	Microbial testing by batch; check FDA recalls	The maker, under its own specifications15
Leaf and flower herbs and teas	Pesticides; weeds harvested with the crop8	Pesticide testing; organic helps but isn’t zero8	The maker; USP limits apply to drug-grade botanicals8
Any supplement with a USP claim	Low-level metals	A product labeled as meeting USP standards	The maker must meet USP limits14

Before you buy, ask the seller four questions. A good company will answer in writing.

• Do you test every batch for lead, arsenic, cadmium and mercury, and against what limits?
• Do you test for pesticides, aflatoxins and germs such as Salmonella?
• Can I see the certificate of analysis for my lot number?
• Where was this herb grown, and how was it dried and stored?

What the evidence shows

Claim	Evidence rating	What it rests on
Some imported Ayurvedic remedies contain dangerous lead levels	Strong evidence	A random-sample product study, FDA lab testing and CDC case reports146
Metal-containing traditional remedies are safe because they are traditional	Evidence says no, or unsafe	Poisonings in adults, pregnant women and infants3457
A “GMP” claim on the label rules out heavy metals	Evidence says no, or unsafe	75% of metal-containing products made that claim2
Organic or wild-collected herbs are free of pesticide residues	Evidence says no, or unsafe	Residues reported in both8
Water extracts carry fewer pesticide residues than raw herb	Promising but early	One Indian study of 1,125 samples9
Drying herbs off the ground lowers aflatoxin	Promising but early	Reviews link ground drying to contamination10

When to get help or report a problem

• You’ve used a remedy that may contain metals. Follow the steps in the lead box above, even if you feel fine³⁷.
• You’re pregnant or trying to conceive. Tell your prenatal clinician about every remedy you use. In New York City, screening found lead in women with no symptoms³.
• A child swallowed a remedy, or you have questions about a poisoning. Call Poison Control at 1-800-222-1222⁶.
• Someone has a seizure, collapses or can’t be woken. Call 911.
• Diarrhea is severe, or the sick person is under 5, over 65 or has a weak immune system. See a clinician; Salmonella can spread from the gut into the blood¹³.
• Report a product. Tell the FDA through MedWatch⁶. In California, you can also reach the state health department’s Food and Drug Branch about adulterated or mislabeled drug products at 1-800-495-3232⁷.

Questions readers ask

The bottom line

Herbal products pick up contaminants the way any farm product can: from sprays, damp drying sheds, dirty processing and, in a few traditional recipes, metals added on purpose. The documented harms are real but concentrated. In the cases here, lead poisoning came from remedies with metals in them, and Salmonella from a raw plant powder.

You can keep using herbs and still protect yourself. Skip formulas that list metals or minerals, favor companies that share batch test results, and ask for a blood lead test if you’ve used a high-risk remedy. Respecting a tradition includes asking where each batch came from.

Related reading

• What gets into supplements that isn’t on the label
• Some herbal pills hide prescription drugs, and others swap out the herb
• How to judge a cup of herbal tea, which is gentle but not automatically harmless
• Third-party tested says what’s in the bottle, not that it works
• Children’s blood lead levels fell 96% without help from any detox product

Sources

1. Saper RB, Phillips RS, Sehgal A, Khouri N, Davis RB, Paquin J, Thuppil V, Kales SN. “Lead, Mercury, and Arsenic in US- and Indian-Manufactured Ayurvedic Medicines Sold via the Internet.” JAMA, 2008;300(8):915-923 (record in CDC Stacks). stacks.cdc.gov
2. Boston University School of Medicine and Boston Medical Center. News release on Saper et al., JAMA study of Ayurvedic medicines sold online. EurekAlert, August 26, 2008. eurekalert.org
3. Centers for Disease Control and Prevention. “Lead Poisoning in Pregnant Women Who Used Ayurvedic Medications from India — New York City, 2011–2012.” MMWR, 2012;61(33). cdc.gov
4. Centers for Disease Control and Prevention. “Lead Poisoning Associated with Ayurvedic Medications — Five States, 2000–2003.” MMWR, 2004;53(26):582-584. cdc.gov
5. Centers for Disease Control and Prevention. “Notes from the Field: Lead Poisoning and Anemia Associated with Use of Ayurvedic Medications Purchased on the Internet — Wisconsin, 2015.” MMWR, 2015;64(32). cdc.gov
6. U.S. Food and Drug Administration. “FDA Warns About Heavy Metal Poisoning Associated With Certain Unapproved Ayurvedic Drug Products.” FDA, content current as of December 2, 2025. fda.gov
7. California Department of Public Health, Occupational Lead Poisoning Prevention Program. “Lead in Ayurvedic Medicines: Information for Clinicians.” CDPH, accessed October 2026. cdph.ca.gov
8. Marles R, chair, USP Botanical Dietary Supplements and Herbal Medicines Expert Committee. “Pesticide Residues” (stakeholder forum presentation). U.S. Pharmacopeia, about 2019. usp.org
9. Koshy R, Yadav S, Rajendran R, Singh VK, Setty MM, Murali B, Agarwal A. “Dietary Risk Assessment and Survey of Pesticide Residues in Herbal Dietary Ingredients from India Collected Between 2017–2020.” Rasayan Journal of Chemistry, 2022;15(3):2032-2041 (abstract, Manipal Academy research portal). researcher.manipal.edu
10. El Darra N, Grimi N, Watson I, El Khoury A. “Editorial: Risk Assessment of Mycotoxins in Food” (summarizing Victor Jeyaraj et al., 2022). Frontiers in Nutrition, 2023. frontiersin.org (open copy: eprints.gla.ac.uk)
11. Elamin A, Sakuda S. “Mechanism of Mycotoxin Contamination of Medicinal Herbs.” Toxins, 2025;17(3):139 (abstract, DOAJ). pubmed.ncbi.nlm.nih.gov
12. Centers for Disease Control and Prevention. “2018 Salmonella Infections Linked to Kratom (Final Update).” CDC, May 24, 2018. archive.cdc.gov
13. Centers for Disease Control and Prevention. “2018 Salmonella Infections Linked to Kratom: Signs and Symptoms.” CDC, 2018. archive.cdc.gov
14. U.S. Pharmacopeia. General Chapter 2232, “Elemental Contaminants in Dietary Supplements” (USP 38–NF 33 text as reproduced by drugfuture.com, a third-party site; not checked against the current official USP–NF). drugfuture.com
15. U.S. Food and Drug Administration. “Import Alert 54-14: Detention Without Physical Examination of Dietary Supplement Products From Firms That Have Not Met Dietary Supplement GMP.” FDA, published September 21, 2026. accessdata.fda.gov