Turmeric is a superb spice with a shaky record as a pill

Key takeaways

• NIH’s LiverTox database says turmeric appears to be the most common cause of herbal liver injury that doctors diagnose in the U.S., though it puts the risk at 1 in 10,000 to 1 in 100,000 users¹.
• A January 2026 review rated all seven pooled analyses it examined on curcumin for knee osteoarthritis “critically low” in quality, even though most reported less pain⁹.
• Chemists say curcumin can fool lab tests, and a former MD Anderson researcher who published widely on it had 30 papers retracted as of October 2022³⁷.
• Since 2019, Italy, France, Australia, the U.K. and Canada have issued warnings, advice or label rules for turmeric and curcumin supplements¹²¹³¹⁵.
• If you take a turmeric capsule and notice yellow eyes or skin, dark urine, nausea or stomach pain, stop it and see a health care professional¹².

Between late 2018 and mid-2019, Italian health officials tracked about 20 cases of hepatitis in people taking turmeric supplements¹³. Testing ruled out contaminants and intentionally added substances¹³. The problem seemed to be the turmeric products themselves.

Since then, the reports have kept coming. LiverTox is NIH’s reference on liver injury from drugs and supplements. It now says turmeric appears to be the most common cause of herbal liver injury that U.S. doctors can detect¹.

That is an odd turn for a spice long used in Indian Ayurvedic, Chinese, Islamic and Thai medicine². It colors curries and rice across South Asia. It is also sold as a supplement for joints, mood, allergies and more².

The short version: turmeric is a superb spice and a disappointing drug. Below, we look at why the science fell short, which uses still hold some promise, and how to keep turmeric in your kitchen without the risks of some capsules.

A ginger-family root with a famous yellow compound

Turmeric is the underground stem, or rhizome, of Curcuma longa, a ginger-family plant grown in India and Southeast Asia². Javanese turmeric is a different plant, so check the Latin name on any label².

Traditional healers used turmeric for indigestion, colds, skin infections, arthritis, belly pain and liver complaints. That’s according to the National Center for Complementary and Integrative Health (NCCIH)². Modern sellers promote it for osteoarthritis, depression, allergies, itching and high cholesterol².

The yellow color comes from a family of compounds called curcuminoids. The main one is curcumin. LiverTox puts curcumin at about 1% to 6% of the dry weight of turmeric extracts, and products vary widely¹.

Turmeric is sold as ground spice, fresh root, tea, capsules of powder and concentrated extracts. Some newer products are built for absorption. They add piperine from black pepper or wrap curcumin in tiny fat particles¹². Label doses run from about 100 milligrams to more than 1,000 milligrams a day¹.

Chemists say curcumin can fool lab tests, and some key papers were retracted

In 2017, chemists from the labs of Michael Walters and Guido Pauli reviewed curcumin’s chemistry in the Journal of Medicinal Chemistry³⁴. Their verdict was blunt. They called curcumin “unstable, reactive, nonbioavailable,” meaning it breaks down fast and the body absorbs little of it³.

They also placed curcumin in two warning categories. The first is PAINS, short for pan-assay interference compounds: substances that seem active in many lab tests because they interfere with the test itself³. The second is IMPS, short for invalid metabolic panaceas. A panacea is a supposed cure-all³.

Our article on animal studies covers why curcumin’s lab results haven’t carried over to people.

Still, the authors left the door open for the plant. They allowed that turmeric preparations may offer some benefits, just far fewer than marketers claim⁴. Their advice was to study turmeric’s many compounds together, a whole-plant idea natural-health readers will recognize⁴.

A second blow came from inside the research world. Bharat Aggarwal, then of the University of Texas MD Anderson Cancer Center in Houston, published widely on natural compounds such as curcumin⁶⁸.

In 2016, the Journal of Biological Chemistry retracted seven of his papers over image problems. Some images had been reused, one flipped and one altered, and several notices cited an MD Anderson investigation⁵. He retired in 2015. By October 2022, his retraction count had reached 30, according to Retraction Watch⁷.

One retracted paper, a 2017 mouse study in Frontiers in Pharmacology, reported that turmeric with its curcumin removed slowed human colon tumors. The journal pulled it after its chief editor examined the raw data and judged the experiments too shaky to support the findings⁸. Retractions don’t prove every curcumin study wrong. They do mean much of the early lab excitement deserves a second look.

What human trials show, use by use

Knee osteoarthritis. This is turmeric’s best-studied use. In January 2026, researchers funded by grants from China’s Zhejiang Province graded seven systematic reviews on it, published from 2017 to 2025⁹. Those reviews pooled 6 to 15 trials each, with 450 to 1,670 people⁹.

Most found less pain and better function than a placebo, a dummy pill⁹. But all seven reviews scored “critically low” on a standard quality checklist. Of 48 results, 37 earned the lowest certainty grade and none earned the highest⁹.

Next to pain relievers such as ibuprofen, called NSAIDs, the largest review found no clear difference. An earlier one judged curcuminoids less effective than ibuprofen for pain⁹. None of the seven reviews reported who paid for the trials they pooled⁹.

Ulcerative colitis. In this inflammatory bowel disease, the trials are few and the reviews disagree. A 2018 review in Nutrients analyzed three oral trials with about 200 people. They took 450 milligrams to 3 grams of curcumin a day for one to six months, on top of standard drugs such as mesalamine¹⁰.

When every randomized patient was counted, curcumin did not beat placebo for remission¹⁰. The authors also dropped a fourth trial because its published results didn’t match its registered plan¹⁰.

A 2020 review in Annals of Gastroenterology cast a wider net: 7 trials and 380 patients, with varied doses and delivery methods. It found about three times the odds of remission with curcumin¹¹. Both reviews studied curcumin as an add-on to medicine, never as a replacement.

Everything else. NCCIH says early research suggests turmeric or curcumin might ease mouth sores from cancer treatment and improve some measures of fatty liver disease². Sellers also promote it for depression, allergies, itching and high cholesterol, but NCCIH’s fact sheet points to no clear benefit for those uses². Overall, it says we don’t know enough to conclude that turmeric or curcumin helps with any health purpose².

Use	Form and dose studied	What the research shows	Evidence level
Knee osteoarthritis pain	Curcuminoid or turmeric extract capsules, varied doses	Less pain than placebo in most reviews, but all seven reviews rated critically low; no clear edge over NSAIDs9	Promising but early
Ulcerative colitis, added to standard drugs	Curcumin 450 mg to 3 g a day by mouth, 1 to 6 months	Two reviews disagree; the stricter one found no significant benefit1011	Promising but early
Mouth sores from cancer treatment	Turmeric or curcumin, forms vary	Initial research suggests relief2	Promising but early
Fatty liver disease	Oral turmeric or curcumin	Some measures may improve; unclear which2	Promising but early
Depression, allergies, high cholesterol	Supplements	Widely promoted; NCCIH cites no clear benefit2	Not enough evidence
Cancer prevention or treatment	Mostly lab and animal studies	Lab signals distorted by test interference; some papers retracted358	Not enough evidence
High-absorption curcumin is risk-free	Improved formulas	Documented liver injury, including deaths112	Evidence says no, or unsafe

The liver problem is rare and real, and contamination doesn’t seem to explain it

How often does it happen? LiverTox puts the odds of noticeable liver injury between 1 in 10,000 and 1 in 100,000 users¹. Trouble typically surfaces a month to four months into use.

The first signs are vague: tiredness, queasiness, no appetite. Darker urine and yellow skin or eyes tend to follow¹.

Concentrated, high-absorption curcumin accounts for most cases. A few involved ordinary ground turmeric or turmeric tea¹. Once people stop the product, the liver usually heals within one to three months. But LiverTox estimates that about 10% of people who become jaundiced may die, a risk that rises if they keep taking it¹.

Genes seem to matter. A gene variant called HLA-B35:01 turned up in more than 70% of cases, compared with 10% to 15% of people in comparison groups¹. The same variant is tied to liver injury from green tea, Garcinia cambogia* and fo-ti products¹.

The Drug-Induced Liver Injury Network, a U.S. research network that tracks these injuries, logged 10 cases from 2011 to 2022. Most were women, and one person died¹.

Regulators in several countries have acted:

Year	Where	What happened
2019	Italy	About 20 hepatitis cases; contaminants ruled out13
2022	Italy	Label warnings required from December 31, 2022, covering liver and bile duct disease, gallstones, pregnancy, breastfeeding, long use and medicines13
2022	France	Food safety agency ANSES advised no more than 153 mg of curcumin a day for a 132-pound adult13
2023	Australia	The Therapeutic Goods Administration (TGA) warned after 18 reports of liver problems, including one death1314
2024	U.K.	The government’s Committee on Toxicity found high-dose supplements can push intake past the safe daily level and called contaminants such as heavy metals an unlikely cause of the cases15
2025	Canada	Health Canada called for label warnings after reviewing 12 Canadian and more than 60 international reports1213
2025	U.S.	A U.S. Pharmacopeia expert panel, which sets supplement quality standards, recommended a cautionary label13

The U.K. and Canada rows come from those governments’ own documents. The rest rely on a 2026 timeline in the trade publication NutraIngredients and on Australian pharmacy reporting¹³¹⁴.

The picture is not settled. Health Canada found that all 12 Canadian cases lacked full clinical details or had other possible explanations¹². Complementary Medicines Australia, the supplement industry group, argued that a link isn’t proof of cause¹³. Still, Health Canada concluded a link was possible and said the risk doesn’t appear to depend on dose or how long someone takes it¹².

Who should skip turmeric supplements

These cautions apply to capsules and extracts, not to curry for dinner.

• Past or current liver disease. Health Canada says to ask a professional first if you have a liver disorder¹². Advice in Australia’s pharmacy magazine goes further. It says people with liver disease should avoid these products, and it flags alcohol use disorder, past hepatitis and autoimmune liver disease¹⁴.
• Gallstones or bile duct problems. Health Canada says most products aren’t recommended for people with bile disorders, and Italy’s label warning covers gallstones¹²¹³.
• Blood thinners. Turmeric products carry a bleeding risk, says pharmacist Geraldine Moses in that magazine. She says people on anticoagulant or antiplatelet drugs should be told not to take them¹⁴. Ask your prescriber first.
• Other medicines. Health Canada advises talking to a health care professional before use if you take any medication¹².
• Pregnancy and breastfeeding. Italy’s warning covers both, and NCCIH says supplements may be unsafe in pregnancy, with little known about breastfeeding²¹³.
• Children and teens. Health Canada hasn’t authorized most turmeric products for people under 18¹².
• Sensitive stomachs. Supplements can cause nausea, acid reflux, diarrhea or constipation².

What’s in the bottle is harder to judge than what’s in the jar

The market is huge. Canada alone has authorized more than 3,000 oral turmeric or curcuminoid products, and Australia’s register listed more than 600¹²¹³.

Lead is a known turmeric problem, and our article on spices and lead covers it in detail. But the U.K.’s Committee on Toxicity judged contaminants such as heavy metals an unlikely explanation for the liver cases¹⁵.

At a 2026 U.S. Pharmacopeia forum, an FDA official asked whether drug interactions or adulteration, such as poor-quality synthetic curcuminoids, lead chromate or pesticides, might play a role¹³. No one has a full answer yet.

The bigger quality question is the formula itself. The improved-absorption designs that marketers promote are the same ones LiverTox links to most cases¹.

Your turmeric profile card

	Spice in food	Capsule or extract
What it is	Ground or fresh rhizome of Curcuma longa2	Powder, curcumin extract, or curcumin with piperine or fat carriers12
Typical amount	A teaspoon or less in a dish	About 100 mg to over 1,000 mg a day on labels1
Best-supported use	Flavor and color	Knee osteoarthritis pain, low-quality evidence9
Main risk	Lead in adulterated spice (see our spice article)	Rare, sometimes severe liver injury112
Skip it if	You’ve had turmeric-linked liver injury1	Liver or gallbladder disease, blood thinners, pregnancy, under 18121314

Buying checklist, if you decide to try a capsule:

• Check the Latin name. It should say Curcuma longa rhizome².
• Find the curcumin amount per day and compare it with France’s 153 mg ceiling for a 132-pound adult¹³.
• Think twice about “improved absorption,” piperine or nano formulas, the types most often linked to liver injury¹.
• Choose a single-ingredient product so you know what you’re reacting to.
• Keep the bottle and lot number in case you need to report a problem.
• Tell your doctor and pharmacist before you start, and set a stop date to judge whether it helps.

Golden milk, with honest expectations

This warm drink is a lovely way to enjoy turmeric as food. No trial has tested it, so treat it as comfort, not medicine.

1. Warm 1 cup of milk or unsweetened plant milk in a small pot over low heat.
2. Whisk in ½ teaspoon ground turmeric, ¼ teaspoon cinnamon and a pinch of black pepper.
3. Add a thin slice of fresh ginger or a pinch of ground ginger.
4. Heat until steaming, but don’t boil. Let it sit two minutes, then strain out the ginger.
5. Sweeten lightly with maple syrup if you like, and serve.

The black pepper adds bite. Its piperine is the compound some supplements add to boost absorption², but nobody has measured what a pinch does in a mug. If you drink golden milk daily, choose Ceylon cinnamon, as our spice article explains. Buy turmeric from a source you trust.

Respecting the spice means not turning it into a drug

Natural health values whole foods, long tradition and skepticism of industry hype. Turmeric’s story tests all three.

The capsules most often tied to harm are not traditional at all. They are engineered to push more curcumin into the bloodstream¹. Meanwhile, the chemists who criticized curcumin pointed back toward the whole plant and its many compounds⁴.

So enjoy turmeric the way cooks have for generations: in dal, rice, soups and roasted vegetables. If you want relief for aching knees or a bowel condition, bring the evidence to your clinician and decide together.

Questions readers ask

The bottom line

Turmeric earns its place in the spice rack. As a supplement, curcumin’s record is weaker than its reputation: early lab signals were distorted by test interference and retractions, and the human trials are small and low in quality.

The risk side is rare but serious. Regulators in Europe, Australia and Canada now warn about liver injury, mostly from high-absorption capsules. Cook with turmeric freely. Treat the capsule like a medicine: check with your clinician, know the warning signs and stop at the first sign of trouble.

Related reading

• Inflammation can harm your heart, but an “anti-inflammatory” label proves little
• Spices can help you cut salt, though some batches have carried lead
• Only 1 in 20 treatments tested in animals wins approval for people
• What happens when you don’t tell your doctor about supplements
• Third-party tested says what’s in the bottle, not that it works

Sources

1. National Institute of Diabetes and Digestive and Kidney Diseases. “Turmeric.” LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, NIH, last updated June 16, 2025. ncbi.nlm.nih.gov
2. National Center for Complementary and Integrative Health. “Turmeric.” NIH, last updated April 2025. nccih.nih.gov
3. Nelson KM, Dahlin JL, Bisson J, Graham J, Pauli GF, Walters MA. “The Essential Medicinal Chemistry of Curcumin.” Journal of Medicinal Chemistry, 2017;60(5):1620-1637 (University of Minnesota record). experts.umn.edu
4. Medical Xpress. “Contrary to Decades of Hype, Curcumin Alone Is Unlikely to Boost Health” (on Nelson KM, et al., Journal of Medicinal Chemistry). January 2017. m.medicalxpress.com
5. Retraction Watch. “Seven Retractions for Prominent Cancer Researcher Brings Total to 18.” August 9, 2016. retractionwatch.com
6. Retraction Watch. “Cancer Journals Retract 10 Papers, Flag 8 More, and Apologize for the Delay.” September 4, 2018. retractionwatch.com
7. Retraction Watch. “Frankincense Extract Paper Is 30th Retracted by Former MD Anderson Researcher Who Once Threatened to Sue Retraction Watch.” October 3, 2022. retractionwatch.com
8. NutraIngredients. “Curcumin Trial Retraction Latest in Long Line for Retired Researcher.” April 13, 2018. nutraingredients.com
9. Chen J, Zhou Q, Yu W, Cao D, Li Y, Chen J, Ye F. “A Critical Review of Systematic Reviews and Meta-Analyses of Curcumin for Knee Osteoarthritis.” Frontiers in Pharmacology, 2026;16:1664319. frontiersin.org
10. Grammatikopoulou MG, Gkiouras K, Theodoridis X, Asteriou E, Forbes A, Bogdanos DP. “Oral Adjuvant Curcumin Therapy for Attaining Clinical Remission in Ulcerative Colitis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.” Nutrients, 2018;10:1737 (University of East Anglia repository). ueaeprints.uea.ac.uk
11. Chandan S, Tummala H, Adler DG, et al. “Curcumin Use in Ulcerative Colitis: Is It Ready for Prime Time? A Systematic Review and Meta-Analysis of Clinical Trials.” Annals of Gastroenterology, 2020;33(1):53-58. openarchives.gr
12. Health Canada. “Summary Safety Review: Turmeric and Curcuminoids for Oral Use: Assessing the Potential Risk of Hepatotoxicity.” Government of Canada, 2025. dhpp.hpfb-dgpsa.ca
13. Sherman A. “Timeline: How Turmeric Supplements Brought Bioavailability and Idiosyncrasy Into Regulatory Focus.” NutraIngredients, August 24, 2026 (trade reporting, cited for regulatory events only). nutraingredients.com
14. Hava C. “TGA Warns of Liver Injury Risk With Turmeric and Curcumin.” Australian Pharmacist, Pharmaceutical Society of Australia, August 23, 2023. australianpharmacist.com.au
15. UK Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment. “Statement on the Potential Risk to Human Health of Turmeric and Curcumin Supplements: Summary and Conclusions” (COT/2024/07). Food Standards Agency, December 2024.