What Are the Side Effects of Turmeric? Stomach, Liver and Kidneys

Turmeric's common side effects are in the stomach: nausea, loose stools, reflux, indigestion and bright yellow stools, often mild and, in trials, about as common as on placebo. The one serious effect is rare: an idiosyncratic liver reaction reported with turmeric supplements, typically one to four months after starting, seen with high-dose, high-absorption products in an Italian series, and reversing on stopping in the published case series.^{1, 2, 3, 4} The UK Committee on Toxicity concluded in December 2024 that, despite limited data, there is reasonable evidence for the link.⁵ Dark urine, pale stools, yellowing of the skin or eyes, nausea or abdominal pain mean stop and seek medical advice the same day.^{6, 7} People with gallstones or liver disease, on anticoagulants, or pregnant or breastfeeding should not take a turmeric supplement without advice. This is the safety spoke of the Wellgard turmeric guide; the medicine-by-medicine table is on who should not take turmeric.

Sources checked on 1 November 2026.

What are the side effects of taking turmeric every day?

Mostly digestive, and mostly mild. In a dose study, single doses of a standardised curcuminoid extract up to 12 g produced minor complaints in 7 of 24 healthy volunteers, none dose-related.⁸ Of suspected reactions to curcuma reported to the MHRA, the commonest, around 16%, were digestive: diarrhoea, constipation, bloating, wind, indigestion and nausea.¹ On UK forums the stomach is the harm people describe: indigestion, burning, "sent me hurtling to the loo", usually in the first weeks and with "high strength" products.

What helps is what the trials did: take it with a meal, split the daily amount across two or three doses, and start at the lowest label dose (how much turmeric a day explains the units). Yellow stools and yellow-tinged urine are the pigment leaving; does turmeric change the colour of your urine explains which colour changes matter. Loose stools lasting more than a few days, blood in the stool, vomiting or pain that wakes you mean stop and see a GP. If reflux or an irritable bowel gets worse on a high-strength extract, stop it.

Is turmeric bad for your liver?

For almost everyone, no; for a few people, yes. Trials have not reported liver toxicity, and in fatty liver disease one analysis of 15 trials found curcumin lowered the liver enzymes ALT and AST slightly, while another of 15 trials found lower AST but no change in ALT.^{6, 9, 10} Italy's herbal-safety database recorded seven cases of acute hepatitis in Tuscany to 2019, all with high-dose, high-absorption products, and Italy's national health institute judged a contaminant an unlikely cause.^{3, 5} The US liver-injury network adjudicated ten cases, eight of them women with a median age of 56, five admitted to hospital and one death; turmeric was confirmed in all seven products tested and piperine (black pepper extract) in three; onset was one to four months; and seven of the ten carried the immune gene variant HLA-B*35:01, which makes up about 6% of gene copies in the general population.² The UK Committee on Toxicity calls the reaction idiosyncratic: rare, unpredictable, possible below the acceptable daily intake, and not something a person can know they are prone to in advance.⁵ In a 2025 series of 11 cases, six people had abnormal liver tests without symptoms, and liver tests normalised in every case after stopping.⁴ The committee's 2021 survey found piperine in 10 of 15 UK supplements, and it named micellar, nano and micro formulations an area of particular concern; its 2025 review adds that the curcumin intake figure may not protect against formulations with increased absorption.^{5, 11} Australia's medicines regulator, the Therapeutic Goods Administration, had received 18 reports of liver problems in people taking turmeric or curcumin products up to 29 June 2023; in four of them no other ingredient was likely to have contributed, and two of those four were severe, one fatal. It judged the risk rare, possibly higher with enhanced-absorption or higher-dose products, and not apparent with turmeric eaten in typical food amounts.¹²

Who should ask for liver tests. Anyone on methotrexate or another medicine processed by the liver; anyone with fatty liver, primary biliary cholangitis or another liver condition, where NHS Wales's medicines advice service advises avoiding turmeric and curcumin and the liver team decides; and anyone with symptoms: dark urine, pale stools, yellow skin or eyes, itching, nausea, loss of appetite or abdominal pain.^{1, 7} Stop and see a GP that day. A suspected reaction to a food supplement is reported to your local authority's food safety team, which works with the Food Standards Agency.¹³ Long-term use is covered on is curcumin safe to take daily. Berberine, another yellow plant alkaloid, has its own kidney and liver page.

Is turmeric bad for your kidneys?

Not at supplement doses in any trial, but turmeric powder is high in soluble oxalate, and that matters for one group. In 11 healthy adults, a turmeric supplement providing 55 mg of oxalate a day raised urinary oxalate significantly; 91% of turmeric's oxalate is the soluble kind, against 6% for cinnamon.¹⁴ One published case describes oxalate kidney damage in a 69-year-old man on long-term turmeric supplements who also had antibiotics and diarrhoea at the time.¹⁵ The oxalate trial's authors concluded that supplemental turmeric can raise kidney-stone risk in susceptible people, so anyone who forms calcium-oxalate stones, or has chronic kidney disease, asks before taking turmeric powder as a supplement.¹⁴ A ginger-and-turmeric shot is a food amount.

Does turmeric affect iron or cause anaemia?

Very rarely, and at very high doses. One documented case: a 66-year-old doctor taking about 3.2 g of turmeric extract a day developed iron-deficiency anaemia with normal endoscopies, and his haemoglobin recovered within two weeks of stopping the turmeric while continuing his iron.¹⁶ Against that, a controlled study of 155 adults found a single 500 mg formulated curcumin dose taken with iron tablets did not blunt the rise in serum iron.¹⁷ The line: if you take iron for anaemia, tell your GP you take turmeric. "Avoid turmeric if you are iron deficient" goes further than one case report and one supplier-funded trial can support.^{16, 17}

Does turmeric make you sweat or change blood pressure, sleep or mood?

These are reports, not findings. One UK forum thread describes sweats and flushing months into turmeric-and-pepper capsules, in people also on prednisolone, which causes sweats itself. A few posters describe a blood-pressure change or extra heartbeats; nearly 7% of suspected reactions to curcuma reported to the MHRA concern heart rate or rhythm, so a new irregular heartbeat is a reason to stop and see a GP.¹ Never change a blood-pressure tablet, or any prescribed medicine, for turmeric, and tell your pharmacist if you take one. The main mood trials are in people with diagnosed depression, where curcumin improved symptoms more than placebo in a pooled analysis its authors judged fragile, and we found none that measured sleep.¹⁸ A new symptom that arrives with a new supplement is a reason to stop it and see.

Who should not take turmeric supplements?

• Gallstones or bile-duct problems. Curcumin makes the gallbladder contract at doses as small as 20 mg (34% in two hours; 72% at 80 mg), and NHS Wales's medicines advice service advises avoiding turmeric and curcumin with gallstones, bile-duct obstruction or any biliary disease, since extracts can trigger biliary colic.^{19, 1}
• Liver disease. See above.
• Anticoagulants and antiplatelets. Curcumin reduces platelet stickiness in the laboratory; in an uncontrolled human study, ten days of a curcumin formulation did not change INR or bleeding time, though a raised INR has been reported in a person on warfarin who started a turmeric product.^{20, 21} Tell your anticoagulant clinic or pharmacist. "Blood thinner" is a caution, never a benefit.
• Black pepper products with regular medicines. Piperine blocks the liver enzyme CYP3A4 and the transporter P-glycoprotein that many medicines use.²²
• Pregnancy and breastfeeding. Curcumin's pregnancy studies are in animals only, so supplement doses have no human safety data; the spice in food is normal.²³
• Surgery and iron tablets. Medicinal turmeric is stopped at least two weeks before planned surgery; if you take iron for anaemia, tell your GP.¹

What we don't know

• How common the liver reaction is: case series cannot give a rate, and the committee called its own data limited.⁵
• Who is prone to it: HLA-B*35:01 carriers may be more susceptible, but nobody can know before taking a supplement.⁵
• Fatty liver: two analyses of the same kind of trials disagree on whether curcumin lowers ALT.^{9, 10}

Frequently asked questions

Is there a downside to taking turmeric every day?

Stomach upset at high strength, and the rare liver reaction described above. Review at 12 weeks and keep it only for a reason you can measure.

Is turmeric good for IBS, gastritis, reflux or colitis?

High-strength extracts can make reflux and loose stools worse, and that is the only firm thing to say. Ulcerative colitis is managed by a gastroenterology team; any supplement is their call, not a self-treatment choice.

What does turmeric do to your skin?

Stains it yellow, temporarily. Itching and swelling are uncommon reported reactions to swallowed turmeric, and allergic dermatitis and hives to turmeric on the skin; no trial of swallowed turmeric has measured skin ageing in healthy adults.¹

Which organ does turmeric affect?

The gut, where most of it stays because curcumin is barely absorbed; the gallbladder, which it makes contract; and rarely the liver.^{8, 19}

What are the 10 serious side effects of turmeric?

There are not ten. The serious ones are the rare liver reaction, gallbladder pain in people with stones, bleeding risk on anticoagulants, iron deficiency at very high doses and oxalate at powder doses. The rest is the stomach.

Sources

1. Welsh Medicines Advice Service (NHS Wales). Turmeric: potential adverse effects. Professional guidance, published 22 October 2024. wmic.wales.nhs.uk.
2. Halegoua-DeMarzio D, et al. Liver injury associated with turmeric, a growing problem: ten cases from the Drug-Induced Liver Injury Network. American Journal of Medicine, 2023. Case series, 10 people, US network cases 2004 to 2022; US National Institutes of Health funding. PubMed 36252717.
3. Lombardi N, et al. Acute liver injury following turmeric use in Tuscany: an analysis of the Italian Phytovigilance database and systematic review of case reports. British Journal of Clinical Pharmacology, 2021. Case analysis, 7 people, and systematic review of 23 published cases; funding not stated on PubMed. PubMed 32656820.
4. Papke DJ, et al. Turmeric supplement-associated hepatitis: a clinicopathological series of 11 cases. Histopathology, 2025. Case series, 11 people; funding not stated on PubMed. PubMed 39381846.
5. 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 (COT/2024/07), summary and conclusions, December 2024. Expert committee statement, including a 2021 survey of 15 UK supplements; read in the UK Government Web Archive, as the committee's own site has withdrawn the page. webarchive.nationalarchives.gov.uk.
6. Akhtar N, et al. Rarely reported cases of hepatotoxicity associated with turmeric- and curcuminoid-containing dietary supplements: a comprehensive review by USP. Pharmaceutical Biology, 2026. Expert committee safety review (US Pharmacopeia); no conflicts declared. PubMed 42364655.
7. NHS. Jaundice. Page last reviewed 22 January 2024. nhs.uk/conditions/jaundice.
8. Lao CD, et al. Dose escalation of a curcuminoid formulation. BMC Complementary and Alternative Medicine, 2006. Dose-escalation study, 24 healthy volunteers, single doses; US National Institutes of Health funding. PubMed 16545122.
9. Vajdi M, et al. Curcumin supplementation effect on liver enzymes in patients with nonalcoholic fatty liver disease: a GRADE-assessed systematic review and dose-response meta-analysis. Nutrition Reviews, 2025. Meta-analysis, 15 trials, 905 people; university research funding. PubMed 38213188.
10. Aragón-Vela J, et al. Does curcumin improve liver enzymes levels in nonalcoholic fatty liver disease? A systematic review, meta-analysis, and meta-regression. Phytotherapy Research, 2024. Meta-analysis, 15 trials, 835 people; Spanish government research funding. PubMed 38965866.
11. Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment. Novel formulations of supplement compounds designed to increase oral bioavailability. December 2025. Expert committee review. gov.uk.
12. Therapeutic Goods Administration (Australia). Medicines containing turmeric or curcumin: risk of liver injury. Regulator alert (safety advisory), published 15 August 2023, covering reports received up to 29 June 2023. tga.gov.au.
13. Food Standards Agency. How to report a food safety or hygiene issue for members of the public. Official guidance, updated 5 August 2026. gov.uk.
14. Tang M, Larson-Meyer DE, Liebman M. Effect of cinnamon and turmeric on urinary oxalate excretion, plasma lipids, and plasma glucose in healthy subjects. American Journal of Clinical Nutrition, 2008. Randomised crossover trial, 11 healthy adults, two 4-week periods; funding not stated on PubMed. PubMed 18469248.
15. Washington O, et al. Oxalate nephropathy and chronic turmeric supplementation: a case report. Jornal Brasileiro de Nefrologia, 2024. Case report, 1 person; funding not stated on PubMed. PubMed 38427579.
16. Smith TJ, Ashar BH. Iron deficiency anemia due to high-dose turmeric. Cureus, 2019. Case report, 1 person; no competing interests declared. PubMed 30899609.
17. Lorinczova HT, et al. Acute administration of bioavailable curcumin alongside ferrous sulphate supplements does not impair iron absorption in healthy adults in a randomised trial. Nutrients, 2021. Randomised placebo-controlled trial, 155 adults, single dose; funded by the curcumin formulation's supplier. PubMed 34371810.
18. Musazadeh V, et al. Efficacy of curcumin in depression: a GRADE-assessed systematic review and meta-analysis of randomized controlled trials. Annals of General Psychiatry, 2026. Meta-analysis, 19 trials; no competing interests declared, funding not stated on PubMed. PubMed 42472817.
19. Rasyid A, et al. Effect of different curcumin dosages on human gall bladder. Asia Pacific Journal of Clinical Nutrition, 2002. Randomised single-blind crossover trial, 12 healthy volunteers, single doses; funding not stated on PubMed. PubMed 12495265.
20. Hu S, et al. Interaction study between antiplatelet agents, anticoagulants, thyroid replacement therapy and a bioavailable formulation of curcumin. European Review for Medical and Pharmacological Sciences, 2018. Uncontrolled before-and-after study in patients on each medicine, 10 to 15 days; funding not stated on PubMed. PubMed 30070343.
21. Welsh Medicines Advice Service (NHS Wales). Turmeric: potential interactions. Professional guidance, published 22 October 2024. wmic.wales.nhs.uk.
22. Bhardwaj RK, et al. Piperine, a major constituent of black pepper, inhibits human P-glycoprotein and CYP3A4. Journal of Pharmacology and Experimental Therapeutics, 2002. Laboratory study in human gut cells and liver microsomes; funding not stated on PubMed. PubMed 12130727.
23. Tossetta G, et al. The multifaced actions of curcumin in pregnancy outcome. Antioxidants, 2021. Narrative review; pregnancy studies in animals only; no conflicts declared. PubMed 33477354.

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This article is general information, not medical advice. If you take any regular medicine, have gallstones or a liver condition, or are pregnant or breastfeeding, ask your pharmacist or GP before taking a turmeric supplement, and never stop or change a prescribed medicine on the strength of one.