Daily ingestion of 2,250 mg turmeric capsules drove 57-year-old Katie Mohan’s liver-enzyme levels to roughly 60 times the upper limit of normal, placing her just short of liver failure and a potential transplant.

Turmeric has become the most frequently documented cause of clinically apparent herbal-related liver injury in the United States, according to the National Library of Medicine and recent studies. Across the broader category of supplements, cases of liver failure that required transplantation rose eightfold between 1995 and 2020.

Today, about one fifth of liver toxicity cases recorded by the NIH Drug-Induced Liver Injury Network are linked to herbal or dietary supplements, with turmeric-associated incidents climbing markedly within that share. Hepatologists therefore report a growing number of supplement-induced liver injuries, even though such events remain uncommon in absolute terms.

The WHO sets an acceptable daily intake for turmeric at 0 to 3 mg per kilogram of body weight, which is about 200 mg for a 68 kg (150 lb) adult. Harvard Health, addressing arthritis pain, advises a maximum of one 500 mg curcumin capsule twice daily, for a total of 1 g or less per day. Many modern turmeric supplements supply at least 2 g daily, already well above both the WHO guideline and Harvard’s recommendation. Mohan’s intake of 2.25 g per day exceeds the WHO limit for her weight by more than tenfold and is more than double Harvard’s suggested cap.

Co-administration of 20 mg of piperine (black pepper extract) increases curcumin bioavailability by roughly twentyfold, thereby imposing a greater metabolic burden on the liver. In addition, limited evidence suggests that curcumin can provoke immune-mediated injury to hepatic tissue.

Early signs of turmeric-induced hepatitis include fatigue, nausea, stomach pain, poor appetite, dark urine, and jaundice. Most cases improve once the supplement is discontinued, because the liver can regenerate if damage is detected early. Mohan required six days of intravenous therapy, and her liver function began to recover during hospitalization. Patient Robert Grafton experienced a similar high-dose turmeric injury at 2,250 mg.

Dietary supplements are not preapproved or actively regulated by the U.S. FDA. “Natural” does not guarantee safety – supplements can contain hidden contaminants, such as lead found in ground turmeric, notes Dr. Dina Halegoua-De Marzio.

Ordinary culinary use of turmeric is considered safe, whereas toxicity arises from concentrated pills taken at pharmacologic doses. Combining high-dose turmeric with piperine can overwhelm hepatic metabolism and cause liver injury.

The U.S. supplement market is a multibillion-dollar sector with limited oversight, and many claimed benefits are supported by low-quality evidence. Social media promotion, including a physician’s Instagram post, led Mohan to begin supplementation.

The points below are distilled from Ars Technica comment threads posted by non-professional, anonymous readers beneath the article “Woman takes 10× dose of turmeric, gets hospitalized for liver damage”

Genetic susceptibility

HLA-B*35:01 is present in about 70 percent of documented turmeric-related hepatitis cases and in roughly 10 to 15 percent of controls, so host genotype is a major determinant of risk. A small subset of people develop marked liver enzyme elevations at curcumin intakes near 200 mg per day, which shows that genetic factors can trigger injury even when consumption stays within guideline limits.

Dose thresholds and toxicology data gaps

Phase I studies have reported curcumin tolerance at doses up to 12,000 mg per day, yet the World Health Organization guideline of 3 mg per kilogram stems from rodent work reduced by a safety factor of 100. The true human toxic threshold therefore remains uncertain and depends on individual context.

Adulteration and field detection

Some growers add lead chromate to raw turmeric to intensify color, introducing significant lead. Diphenylcarbazide colorimetry or portable X-ray fluorescence can identify this contamination during rapid field checks.

Metabolic interactions

Capsaicin and grapefruit furanocoumarins inhibit several cytochrome P450 isoforms and can raise circulating curcumin or drug concentrations, while St. John’s wort induces the same enzymes and can lower them. Piperine from black pepper produces a similar inhibitory effect and is routinely combined with curcumin in supplements.

Regulatory and market context

The Dietary Supplement Health and Education Act of 1994 exempts supplements from U.S. premarket approval, so many high dose turmeric products reach consumers through lightly scrutinized retail and multi level marketing channels.

Illustrative toxicology principles

Water intoxication can cause fatal hyponatremia, acetaminophen overdose predictably injures the liver, and botulinum toxin is lethal in gram quantities yet therapeutic in micrograms. These examples reinforce that dose and context govern risk for any substance, including curcumin.