What Is Kava, and Are There Health Benefits to Drinking It?

For thousands of years, people have used herbs and plants to treat illness and support health. Kava is one such remedy that’s been around for a long time — and has recently grown in popularity. People have been turning to kava to ease anxiety and stress, among other uses. But what exactly is kava, and does research support its health benefit claims? 

What is kava?

Kava — also called kava kava — is a drink or extract made from the kava root plant, Piper methysticum. The plant is a member of the pepper family and grows on the Pacific Islands. Indigenous people of these islands have used kava for centuries. In local languages, the word “kava” refers to the drink’s bitter taste.

What is kava used for?

People sometimes take kava for anxiety. In fact, anxiety and stress relief are among the most common reasons that people take it.

Other traditional uses of kava include: 

• Pain relief

• Relaxation

• Sacred ritual purposes 

Scientists are also studying kava’s effects and its potential uses in treating inflammation, brain-related conditions, and cancer. But these are new areas of research. 

What is in kava, and what does it do?

The active substances in kava are called kavapyrones, or kavalactones. If you’re wondering what kavalactones are, you aren’t alone. Scientists don’t fully understand how these substances work. But these active substances may affect how nerves send messages throughout the body and the brain.

For example, scientists know that kava affects GABA (gamma aminobutyric acid) nerve receptors. Alcohol and certain medications for anxiety and pain also work on these receptors. For some people, taking kava results in a feeling of calm or helps with pain relief. So, this may point to how kava works, but more research is needed.

What are the effects of kava?

The effects of kava can depend on your body size, how much you take, and what other medicines you’re taking. Overall, kava effects are somewhat similar to those of alcohol. Kava can make you feel more relaxed and sleepy. You might feel a greater sense of well-being. Because kava relaxes muscles, you might have a slower response time. Some researchers feel this warrants more research to see if driving while using kava might lead to motor vehicle accidents.

Kava benefits

The research on kava’s benefits is limited. Here, we’ll break down what the science says about possible benefits of kava.

Kava and anxiety

There’s evidence that kava may be an effective natural remedy for anxiety, when it’s used for a few weeks. Kava may help with short-term stress and worry, especially if a particular situation is the root cause. Kava may also help with symptoms of anxiety during menopause. 

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But, when it comes to long-term use, the data is less clear. Some studies evaluated the use of kava for 4 months and found that kava may not help generalized anxiety. Keep in mind that there’s no data on the safety of using kava as a long-term treatment for anxiety.

Kava and sleep 

Some research suggests that kava might also help with sleep. In one study, participants took 200 mg of kava daily. After 4 weeks, those who took kava reported better quality of sleep. Kava may also be helpful for stress-induced insomnia. But more research is needed to know for sure if it helps. 

Kava and post-traumatic stress disorder (PTSD)

It’s possible that kava may be helpful with treating post-traumatic stress disorder (PTSD). But there isn’t a lot of research on kava and PTSD. Researchers are in the early stage of investigating kava as a tool for therapy. 

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Kava and pain

Traditionally, kava has been used as a pain reliever. Some animal studies suggest that kavalactones can decrease some types of pain. But there isn’t evidence to show that it works to lower pain in people. 

Kava side effects

Many people assume that herbal remedies, like kava, are free of side effects because they come from nature. But that’s not always the case. 

Here are some of kava’s possible side effects: 

• Headache

• Dizziness

• Sleepiness

• Feeling down or depressed

• Diarrhea

• Numbness in the mouth, throat, or tongue

• Liver damage

Kava interactions 

Although serious side effects are uncommon when taking kava alone, it can interact with certain medications and substances. 

Talk with a healthcare professional or pharmacist before taking kava with:

• Alcohol

• Medications that cause drowsiness, like sedatives

• Medications that affect the liver, like acetaminophen (Tylenol)

• Anxiety medications, like benzodiazepines

• Muscle relaxants

• Medications used to treat Parkinson’s disease

• Medications that are similar to dopamine, as well as those that block dopamine, like haloperidol (Haldol)

• Monoamine oxidase inhibitors (MAOIs)

The potential risks of these interactions include liver damage and coma. And, keep in mind, this isn’t a complete list of substances that kava might interact with.

Kava drinks and supplements

Traditionally, kava is consumed as an herbal tea. Kava drinks are made by grinding up kava roots into a powder, which is then stirred into water or coconut milk. 

Apart from the drinkable forms (like kava tea), kava supplements are also available as:

• Powders

• Extracts

• Tablets

• Capsules

There isn’t much research comparing different forms of kava supplements. Most studies have used kava extracts, and there aren’t any official dosing guidelines. Typical doses range from about 70 mg to 280 mg per day, but it’s best to check with a trusted healthcare professional before starting.

Is kava safe?

Some research studies have found that kava is safe in doses of less than 400 mg a day. But the FDA doesn’t classify kava as a “generally recognized as safe” supplement. That’s because kava has been linked to cases of severe liver injury — including liver failure. In one case, a liver transplant was needed. 

In fact, in some countries — including Canada and the U.K. — kava is banned due to concerns about liver toxicity. The FDA hasn’t banned kava, but it did issue a consumer advisory in 2002 cautioning healthcare professionals and consumers about the risk of liver damage. 

Kava and liver damage

In recent studies, the risk of liver damage related to kava appears to be small but real. Liver damage from kava may be mild or severe. In most cases, the damage is reversible and improves after a couple of months of not taking kava. 

More recent studies suggest that the risk of liver damage is higher with:

• Doses of kava that are too high

• Poor-quality kava

• Kava in combination with alcohol and medications that affect the liver

• Long-term use of kava

What happens if you take too much kava? 

If you take too much kava at once, you may experience:

• Weak or uncoordinated muscles

• Nausea

• A slight fever 

• Dilated (large) pupils 

• Red eyes

• Feeling very sleepy

People who take a lot of kava over longer periods of time may experience: 

• Mood changes

• Weight loss

• Dry and scaly skin

• Shortness of breath

• A loss of interest in relationships and activities

• More frequent infections

• Liver problems

If you’re worried that you’re having an abnormal reaction to kava, call Poison Control at 1-800-222-1222. For serious symptoms, call 911 or go to the nearest emergency room.

Who should not take kava?

For most adults, limited amounts of kava are likely safe. But kava may be riskier for some people. 

Avoid kava if:

• You have liver disease.

• You’ll be driving or operating heavy machinery.

• You’re also drinking alcohol or taking medications that cause sedation. 

• You’re pregnant or breastfeeding.

• You’ll be having surgery or a procedure involving anesthesia.

Talk with a healthcare professional if you have questions about or are considering taking kava. Be sure to provide them with a full list of your medications and supplements, so they can help you weigh the benefits and risks of taking kava. 

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Written by:

Anne Jacobson, MD, MPH

Anne Jacobson, MD, MPH has been a board-certified physician since 1999. She was a full-scope family physician (inpatient, outpatient, obstetrics, and office procedures) in the Cook County Ambulatory Health Network for 15 years.

Edited by:

Alex Eastman, PhD, RN

Alex Eastman, PhD, RN, is a California-based registered nurse and staff medical editor at GoodRx, where he focuses on clinical updates and Latino health.

Reviewed by:

Karen Hovav, MD, FAAP

Karen Hovav, MD, FAAP, has more than 15 years of experience as an attending pediatrician. She has worked in a large academic center in an urban city, a small community hospital, a private practice, and an urgent care clinic.

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