Turmeric Side Effects

NCCIH, updated April 2025, says conventionally formulated oral turmeric is likely safe for up to 2 or 3 months, and that highly bioavailable formulations may harm the liver. It says liver damage has been reported in some people who took those formulations. The symptoms it tells people to act on are fatigue, nausea, poor appetite, dark urine, or jaundice (NCCIH).

Halegoua-DeMarzio and colleagues, in the U.S. Drug-Induced Liver Injury Network (American Journal of Medicine, 2023), describe 10 turmeric-associated cases enrolled from 2004 to 2022, all of them since 2011. Eight of 10 were women. Median age was 56. Five were hospitalized and one died of acute liver failure. Seven carried HLA-B*35:01, an allele frequency of 0.450 versus 0.056–0.069 in population controls. The authors describe a latency of 1 to 4 months. Chemical analysis confirmed turmeric in all 7 products tested, and 3 of those 7 also contained piperine. The authors say the rise in cases may reflect usage patterns or more combination with black pepper. This is a case series. It shows an association. It does not say how common the injury is (PMID 36252717).

Likhitsup and colleagues (JAMA Network Open, 2024) estimated from NHANES that about 15.6 million U.S. adults used at least one of six botanicals with reported liver liability in the past 30 days. Turmeric-containing products were the most commonly used of the six. That paper is an exposure survey, not an injury count (PMID 39102266).

A 2026 USP expert-committee review recommends this label caution, quoted from the paper: “Liver problems have been reported very rarely in people taking supplements containing turmeric and/or curcuminoids. Consult your health-care practitioner before using this product if you have a history of liver problems. Stop using this product if you develop symptoms such as abdominal pain, dark urine, or jaundice (yellowing of the skin or eyes), and seek medical advice.” (PMID 42364655).

The best-turmeric guide could not open NIH LiverTox in a browser on October 28, 2026. We did not get a LiverTox incidence figure on November 3 either, so none is quoted.

Feng and colleagues (2022) pooled 15 studies of curcuminoids alone, 1,670 patients, and reported that adverse events were not more frequent than placebo. They also rated the evidence low quality with substantial heterogeneity (PMID 36261810).

Hsiao and colleagues (2021), 11 studies and 1,258 participants, found no significant difference in adverse events between 1,000 mg a day or more and lower doses (PMID 34537344).

Henrotin and colleagues (2019) randomized 150 people with knee osteoarthritis for 3 months to a branded Curcuma longa extract at two doses or placebo. The number of product-related adverse events was higher in the high-dose group. That trial tested one commercial product (PMID 31351488).

Trial safety over weeks or a few months is not the same record as the liver-injury case series. Both can be true: common short-trial complaints can be uncommon, and rare severe injuries can still be real. What those trials measured on pain scores, and the limits of that evidence, is on best turmeric supplement.

NCCIH does not name blood thinners specifically. It says to talk with your provider if you take any medicine. A 10-day study of one phytosome product, Meriva, found no significant change in bleeding time or INR in people already on aspirin, clopidogrel, ticlopidine, warfarin, or dabigatran (PMID 30070343). The study was short, it tested one product, and it does not show safety for other products or for longer use.

NCCIH says turmeric supplements may be unsafe in pregnancy, and that little is known about doses above food amounts while breastfeeding.

Piperine, from black pepper, raised curcumin absorption in a small 1998 human report. It was also in 3 of 7 products tested in the DILIN series. That does not prove pepper caused the injuries. It is a reason to notice pepper on a high-absorption label. Lead in turmeric spice is a different topic, on the best turmeric page.