These Herbals Can Cause Liver Damage

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More than half of American adults take dietary supplements regularly, often believing they’re doing something good for their health. After all, supplements are marketed as natural and safe. But research paints a more complicated—and sometimes alarming—picture.

Over the past 25 years, cases of liver failure linked to supplements have skyrocketed, increasing nearly eightfold. Today, these products are responsible for almost a quarter of all reported liver toxicity cases in the United States. In some instances, the damage was so severe that patients needed a liver transplant—or didn’t survive at all.

So, which herbal supplements are most likely to harm your liver, and what can you do to protect yourself?

Herbal Supplements and Liver Damage

Weight-loss and bodybuilding supplements are among the most notorious for causing liver injury. But they’re not alone. More reports are emerging about other herbal products—and even certain vitamins and minerals—being connected to liver toxicity. While these aren’t as strongly linked as weight-loss formulas, the growing number of cases is worth taking seriously.

herbal-supplements-that-harm-the-liver — Herbal supplements linked to liver damage

Aloe Vera

You’ve probably seen aloe vera in skincare products, but it’s also used in food and medicine. The gel from the leaf is sometimes eaten or used for digestive support, while the latex from the leaf rind is used in powders and extracts for constipation, detox, or weight loss.

Most reported liver injuries are linked to the latex, not the soothing gel. These cases are rare and usually mild, and most people recover after stopping the product. No fatal cases have been reported so far, but researchers still don’t know which compounds in aloe cause the problem.

Ashwagandha

Ashwagandha is one of the most popular herbs in Ayurvedic medicine. People take it to reduce stress, increase energy, and improve overall well-being. It’s usually considered safe, but in recent years, reports of liver injury have surfaced in people using supplements labeled as containing ashwagandha.

Most individuals recover within one to four months of discontinuing it. The exact cause remains unclear—some researchers blame natural compounds called withanolides, while others point to contamination or mislabeled products.

Black Cohosh

Black cohosh is widely used to relieve menopause symptoms and balance hormones. In clinical trials, it hasn’t shown a strong connection to liver injury. However, in real-world cases, over 50 reports have linked “black cohosh” supplements to liver damage.

Some people may simply be more sensitive to it, but in many cases, the products weren’t pure black cohosh at all—they were contaminated or substituted with other herbs, like certain Chinese Actaea species. Mislabeling or adulteration may be the real culprit.

Butterbur

Butterbur is a plant-based remedy used for migraines, allergies, and breathing issues. The danger lies in naturally occurring compounds called pyrrolizidine alkaloids, which can cause serious liver damage.

Reputable butterbur supplements are supposed to have these toxins removed, but contamination still happens. When problems occur, symptoms such as nausea and jaundice usually appear within two to twelve weeks, and most people recover once they stop taking it.

Greater Celandine

Greater celandine comes from the poppy family and is often used to treat indigestion and stomach problems. In Europe, more than a dozen cases of liver injury have been tied to this herb. Interestingly, there have been no reports from North America. Scientists still aren’t sure which compound in celandine triggers the damage.

Kava Kava

Kava kava is used to ease anxiety, stress, and insomnia—but it has a dark side. It’s been linked to severe hepatitis and even liver failure requiring transplants. In some cases, deaths have been reported.

The FDA issued warnings years ago but stopped short of banning it. Later research found that the worst outcomes often involved high doses, raw unprocessed kava, or mixing it with alcohol. Even so, more than 100 cases of kava-related liver injury have been documented worldwide. The takeaway? Use kava sparingly and with caution.

Kratom

Kratom, a plant from Southeast Asia, acts on the brain’s opioid receptors and can produce stimulating or sedative effects. Some people use it recreationally or for pain relief.

Chronic use has occasionally been linked to liver injury, but it’s difficult to know whether kratom itself is the cause, since many users also drink alcohol or take other substances that strain the liver.

Polygonum Multiflorum

Also known as Fo-Ti or Chinese knotweed, Polygonum multiflorum has been used in traditional Chinese medicine for centuries. People take it for everything from back pain and dizziness to reversing gray hair.

Unfortunately, it’s also one of the more dangerous herbs for the liver. Many cases of acute liver injury have been reported in China, Korea, and Japan. Most patients recover once they stop taking the supplement, but about 10% of severe cases have resulted in liver failure or death. Researchers suspect certain plant compounds, like emodin, may trigger an autoimmune reaction that attacks liver cells.

Red Yeast Rice

Red yeast rice is a fermented rice product often used to lower cholesterol naturally. Clinical studies haven’t shown a strong connection to liver damage, but there are occasional real-world reports of injury.

The likely culprit is lovastatin—the same active ingredient in some prescription cholesterol drugs. In sensitive individuals, it can produce a toxic byproduct in the liver, leading to inflammation or damage.

Turmeric

Turmeric has long been praised for its anti-inflammatory properties, and for years it was considered completely safe. But that changed when supplement makers began developing “high-bioavailability” forms—formulas designed to boost curcumin absorption using piperine (from black pepper) or fat-based systems.

These enhanced versions have been linked to rare cases of liver injury. Experts believe that in certain people, genetic factors may trigger an immune response that mistakenly harms the liver. Regular turmeric remains safe for most people, but high-dose or concentrated curcumin supplements carry added risks.

Skullcap

Skullcap is a traditional Native American herb often taken as a tea or capsule for anxiety, stress, and insomnia. A few reports have connected it to liver injury, but further investigation showed that many of these supplements were contaminated with other toxic herbs like germander—or weren’t skullcap at all.

That means some of the reported liver issues may have been caused by mislabeling rather than the herb itself.

Vitamins and Minerals That Can Harm the Liver

Even essential vitamins and minerals can cause liver damage if you take too much. While normal amounts found in food or standard supplements are usually safe, overdosing—whether accidentally or intentionally—can overwhelm the liver and lead to serious problems. It’s a good reminder that more isn’t always better when it comes to nutrients.

Copper

Copper is an important trace mineral your body needs in small amounts, and it’s commonly found in multivitamins. For most people, the small doses in supplements are harmless. However, trouble starts when you get too much. High levels of copper—whether from accidental overdose, contaminated supplements, or intentional misuse—can cause both acute and chronic liver injury.

In children, even something as simple as swallowing a few copper coins can cause poisoning. Chronic liver damage can also occur in people with Wilson’s disease, a rare genetic condition that causes copper to build up in the body over time.

Iron

Iron helps your body produce red blood cells and prevent anemia. It’s a vital mineral—but like many good things, too much can be dangerous. In normal doses, iron supplements are safe. But taking high amounts, whether intentionally or by accident, can cause severe toxicity.

Iron poisoning can lead to acute liver injury, organ failure, and even death. It’s considered a direct toxin to the liver, meaning damage occurs only after very high exposure. That’s why it’s especially important to keep iron supplements out of children’s reach—they can be extremely toxic in large doses.

Vitamin A

Vitamin A plays a crucial role in vision, immune health, and maintaining healthy skin and bones. It’s a fat-soluble vitamin, which means your body stores the excess in your liver instead of flushing it out. When you take too much—typically more than 40,000 IU per day—it can build up and cause toxicity.

This condition, known as hypervitaminosis A, can also develop from eating large amounts of animal liver, such as cod, bear, or seal liver, which naturally contains high concentrations of vitamin A. Over time, excess vitamin A can lead to liver scarring, fibrosis, and even serious liver failure.

Herbs That Are Not Harmful to the Liver

Not every herb with a bad reputation actually deserves it. Some are misunderstood and, in fact, may even help protect the liver.

Take milk thistle, for example. Many people assume it harms the liver, but there’s no scientific evidence to support that claim. In fact, researchers are studying milk thistle for its potential liver-protective properties. So far, there have been no credible reports linking it to liver injury.

St. John’s wort is another example. It’s best known for interacting with medications—sometimes in significant ways—but it doesn’t directly damage the liver. Large studies on its use for depression show no evidence of liver toxicity. However, St. John’s wort can affect how your liver processes certain drugs by speeding up the breakdown of medications, which can change how well those medications work.

Dr. Brian’s Advice

Here’s the truth: no supplement is completely risk-free. That doesn’t mean you should avoid them altogether—millions of people take supplements every day without any issues. The real challenge is unpredictability. Two people can take the exact same supplement in the same dose, yet have totally different experiences. One might feel a boost in energy, while the other could develop signs of liver stress. Genetics, existing health conditions, and even other medications all play a role.

So, it’s not that supplements are guaranteed to harm your liver—but if you’re one of the unlucky few, you could be damaging your liver slowly and silently without realizing it. By the time symptoms appear, the damage could already be serious.

The safest approach? Keep things simple. Only take supplements you truly need. Choose trusted, reputable brands with transparent ingredient lists. Stick to recommended doses, and never assume that “natural” means “safe.” Always check what’s in your supplements and talk to your doctor before starting something new.

Think of supplements like you would prescription medication—they can be beneficial when used wisely and with purpose. But taking them just because you saw someone online recommend them isn’t worth the risk to your liver—or your health.

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Citations

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