What is kava?
Kava (kava kava) is the root of a plant that South Pacific islanders have traditionally made into a drink. It contains compounds that calm the mind, so it's been used for anxiety, stress, insomnia, premenstrual irritability (PMS) and menopause-related heart flutters.
The problem is that its risk to the liver far outweighs its benefits.
The risk to know first: liver damage
Among supplements that have caused liver damage, kava is placed in the highest-risk category. In LiverTox, the US National Institutes of Health's liver toxicity database, it's Category A — "well established as a cause of liver injury."
- There have been several reports of people who needed liver transplants or died.
- Some people developed acute hepatitis or liver failure within just a few weeks of starting it.
- In one case, a person taking 240 mg a day for 4 months for low mood developed acute liver failure and needed a liver transplant.
- It interferes with the liver enzymes that break down medications, so it easily clashes with other drugs and supplements.
- Some experts also point out that it may lead to dependence, making you want to keep taking it.
Especially don't take it if
- You have high liver enzymes or liver disease
- You drink alcohol often
- You take prescription medications regularly
- You take other supplements that strain the liver (like weight-loss products)
Honestly, we don't recommend it even if none of these apply to you. If sleep or anxiety is making life hard, many experts say it's safer to talk to your doctor than to find kava and take it on your own.
How to find hidden kava in sleep and stress supplements
Kava is more often mixed into blends with names like "Sleep," "Calm," "Stress" or "Relax" than sold on its own.
- Look at the Supplement Facts panel on the back of the label.
- If you see any of Kava, Kava Kava, Piper methysticum or Kavalactones, it contains kava.
- If it does, switch to a different product.
If you're already taking it
1. We recommend stopping today.
2. If you have any of these symptoms, see a doctor right away and get a liver test.
- Yellowing of the whites of your eyes or skin
- Dark brown urine
- Extreme, unexplained tiredness and loss of appetite
- Pain in the upper right side of your belly
3. When you go, bring the product you were taking and show the ingredients.
Some sources say that if you must take it, keep it under 6 months and take breaks on and off. But liver damage has occurred even with short-term use, so this isn't a reliable way to stay safe.
Medications and conditions to watch
- Caution Prescription medications in general — Interferes with liver enzymes that break down drugs, which can change how they work — don't take them together
- Caution Supplements that strain the liver — Can further raise the risk of liver damage
- Caution Alcohol — Can further raise the risk of liver damage
Frequently asked questions
Is kava liver toxicity really dangerous?
Yes. There are several cases that led to liver transplants or death, and it's in the category with the strongest evidence of liver injury. We recommend not taking it.
Why is kava sold in the US?
In the US, supplements don't need approval before they're sold, so it's still on the market. Sales have been blocked or stopped in places like Europe, Canada and South Korea.
Is a small amount of kava okay?
Liver damage has happened after just a few weeks, so it's hard to define a safe amount or length of time. If sleep or anxiety is the problem, it's better to look for other options.
How can I tell if a sleep supplement contains kava?
Look in the label's Supplement Facts for the words Kava, Kava Kava, Piper methysticum or Kavalactones. If any of them appear, the product contains kava.
I stopped taking kava. Do I need to get tested?
If your eyes or skin turned yellow, your urine got dark, or you felt extremely tired, be sure to get a liver test. Even without symptoms, if you took it for a long time, check your liver enzymes at your next checkup.
Related concerns
Last updated 2026-10-12