When it comes to liver health, many doctors advise against taking herbal supplements without close medical supervision. Take the case of a recent study published in BMJ Case Reports that claims turmeric supplements may have caused serious damage to a woman’s liver, resulting in hepatitis, Prevention.com reports.

Turmeric is one of the most widely used supplements in the wellness world, with experts touting the herb’s many benefits, including its alleged anticancer and anti-inflammatory properties and ability to fight heart disease and Alzheimer’s disease. However, when taken in high doses, the herb could be dangerous, this study suggests.

According to the report, a 71-year-old woman was taking the supplement (along with 20 other medicines and supplements) for her heart health and developed autoimmune hepatitis. This form of hepatitis—or liver inflammation—was caused by her body’s own immune system turning against her liver cells, a condition that could eventually lead to cirrhosis, or scarring of the liver, and liver failure.

Doctors later discovered that the woman had been taking a high-dosage turmeric supplement for eight months prior to the incident. It was only after the administration of a liver enzyme test that doctors were able to diagnose her condition. According to the report, she had not told her doctors she was taking the supplement.

To follow up the study, authors conducted a review of 35 previous studies related to turmeric supplements. They found that around 5 percent of those who took the herb in high doses suffered liver problems as a result of taking it. But this is the first report linking autoimmune hepatitis to turmeric use.

“Bringing supplements out of the shadow of medical care and into a well thought-out discussion where both physicians and patients are knowledgeable is the key to preventing isolated cases such as these,” said Tasneem Bhatia, MD, an integrative medicine specialist involved in the study.

Authors concluded their report by urging patients to tell their doctors about all the supplements they are taking and to be careful of the doses they take.