The Health Benefits of Kava

May Reduce Anxiety and Improve Sleep in People With Insomnia

Kava (scientific name Piper methysticum) is a tall shrub in the pepper family that grows in the Pacific islands. Pacific Islanders have traditionally used kava in ceremonies to bring about a state of relaxation. The name kava means "bitter" in the Tongan language.

The root of the plant is traditionally used to make beverages that have a mild to moderate sedative effects. It is also said to elicit feelings of euphoria. In some traditional cultures, kava is consumed in the same way that alcoholic beverages are here.

Today, many people buy kava supplement to treat anxiety. Although kava in its traditional form poses an "acceptably low level of health risk" according to the World Health Organization (WHO), kava extracts and supplements may cause liver toxicity if overused or consumed on an ongoing basis.

side effects of kava kava

Verywell / Brianna Gilmartin

Also Known As

  • Kava kava
  • Kawa kawa
  • 'Ava (Samoa)
  • 'Awa (Hawaii)
  • Malak (Vanuatu)
  • Rauschpfeffer (Germany)
  • Sakao (Pohnpei)
  • Yaqano (Fiji)

Kava Health Benefits

Beyond its recreational and ceremonial use, kava is commonly used in alternative medicine as a natural anxiolytic (anxiety-reducing) drug. It may also improve sleep in people with insomnia, often with fewer side effects than pharmaceutical or over-the-counter sleep aids.

The compounds in kava root believed to offer mood-altering properties are called kavalactones. There are 18 different kavalactones identified thus far. Little research has been done to pinpoint their exact mechanisms of action or evaluate which compounds are more active than others.


The current body of evidence suggests that kava may aid in the treatment of anxiety, although there remains contention as to how effective a drug it really is.

According to a 2002 review of studies involving seven clinical trials and 645 people, kava was deemed to be an "effective symptomatic treatment option for anxiety," even though the effect was considered "small" by the researchers.

The findings were supported by a 2011 review from Australia in which kava was considered more effective in treating generalized anxiety disorder (GAD) than a placebo. With that being said, a traditional kava beverage was recommended over supplements for safety reasons, along with regular liver enzyme testing to avoid toxicity.

A 2013 randomized controlled trial found that kava was effective in the treatment of generalized anxiety disorder. The results showed a significant reduction in anxiety and by the end of the trial, 26% of participants in the kava group experienced remission from their anxiety symptoms.


Most of the research devoted to the use of kava for insomnia is limited to animal studies. It is believed that a specific type of kavalactone, called kevain, may provide the drug's sedative effect.

Of the available human research, one small study from Germany concluded that people provided a daily 200-milligram kava extract experienced significant relief from insomnia after 14 days.

Despite the promising results, the conclusions were undermined by the subjective nature of "quality of sleep" questionnaire. Based on the study measures, even people provided a placebo had significant improvements in sleep.


Kava also has inflammatory properties, which may make it useful in the treatment of conditions in which inflammation plays a role. Some research suggests that the modification of kava compounds may be useful for increasing these anti-inflammatory effects.

However, more research is needed and some reports have suggested that kava exposure can actually induce an inflammatory response. 


Some research has found that kava may help reduce the risk of cancer. Studies have found that kava may have preventative effects on lung cancer in mice. Other research has also shown that kava might have preventative effects on prostate cancer, colon cancer, and urothelial cell cancer.

However, such results have only been observed in animal studies, and more research is needed to understand the mechanism of action and its effects in humans.

Side Effects of Kava

The use of kava remains controversial. While proponents believe that kava can be safely used for the short-term treatment of anxiety, others contend that the potential risks far outweigh the benefits.

Even for short-term use, side effects like indigestion, mouth numbness, rash, headache, drowsiness, and visual disturbances are common. The consequences of long-term use may, in some cases, be catastrophic.

Liver Damage

In March 2002, the U.S. Food and Drug Administration (FDA) warned consumers and health professionals about the risk of liver damage associated with kava use. Case reports have linked kava with liver toxicity, including hepatitis, cirrhosis, liver failure, and even death. 

Many of these cases were linked to pre-existing liver disease, excessive kava doses, and heavy alcohol use. It is still unclear whether the liver toxicity was the result of kavalactones, contaminants found in low-quality extracts, or the organic solvents (such as acetone or ethanol) used to make kava extracts and supplements.

Even though the WHO suggests that water-based kava beverages are "safer," the agency concedes that moderate to heavy consumption can significantly raise liver enzymes. The WHO also warned that toxicity appears linked to the quality of the raw kava root, contamination of the root during storage, and the use of other herbal drugs with kava.

In the aftermath of the warning, several countries have restricted the sale of kava within their borders. To date, only Germany, Canada, Poland, and Switzerland has banned the use of kava in any form. In the United States, kava is classified as a dietary supplement and can be legally purchased for personal use.

Call your doctor if you experience signs of liver toxicity, including persistent fatigue, weakness, nausea, vomiting, loss of appetite, dark urine, clay-colored stools, or the yellowing of the skin or eyes (jaundice).

Precautions and Contraindications

If you intend to use kava for recreational or medicinal purpose, there are several things you should consider beforehand:

  • Kava's effect on the neurological system is poorly understood. As such, it should not be used in people with clinical depression, bipolar disorder, or schizophrenia.
  • Kava should be avoided in people with Parkinson's disease as it can potentially make the symptoms worse.
  • Kava may interfere with blood clotting. It should not be used by people with bleeding disorders. You would also need to stop using kava at least two weeks before surgery to avoid excessive bleeding.
  • Kava can cause drowsiness and impair your judgment, reflexes, and visual acuity. Do not use kava if you plan to drive or operate heavy machinery.
  • Kava should be avoided in people with alcoholism, liver disease, pulmonary hypertension, low blood pressure (hypotension), or kidney disease.

Due to the lack of safety research, kava should never be used in children, pregnant women, or nursing mothers. Some studies have suggested that kava can be readily transmitted in breastmilk.

Drug Interactions

Kava can interact with a number of drugs and supplements. In some cases, it may enhance the effects of the accompanying drug. In others, it may reduce the effectiveness of the accompanying by competing for the same liver enzymes, called CYP450, used to metabolize kava.

Speak with your doctor if you are using (or intend to use) kava with any of the following medications:

  • Sedatives and over-the-counter sleep aids
  • Tricyclic antidepressants like Tofranil (imipramine)
  • Monoamine oxidase inhibitors (MAOI) used to treat depression
  • Benzodiazepines like Valium (diazepam) or Ativan (lorazepam) used to treat anxiety
  • Diuretics ("water pills") like Lasix (furosemide)
  • Blood thinners like Coumadin (warfarin) or Plavix (clopidogrel)
  • Levodopa used to treat Parkinson's disease
  • Proton pump inhibitors like Prevacid (lansoprazole) and Prilosec (omeprazole)
  • Antipsychotics like Abilify (aripiprazole), Clozaril (clozapine), and Seroquel (quetiapine)

Dosage and Preparation

There are no guidelines for the appropriate use of kava. Kava is generally sold in the United States in capsule, soft gel caps, extract, powder, and tea forms. There are also "wild-crafted" dried roots used to make tinctures, teas, and beverages.

Most capsule formulations are offered in doses ranging from 50 milligrams to 100 milligrams. Most experts recommend that you take no more than 250 milligrams per day and limit your use to no more than three months.

Be advised that liver damage has been known to occur after one month of kava use with normal doses.

What to Look For

Kava, like all dietary supplements, is largely unregulated in the United States. Do not assume that this means the drug is safe. The classification simply means that the manufacturer is responsible for ensuring the safety of the supplement, not the FDA. While this relieves the manufacturer of the burden of clinical research, it can sometimes leave the consumer vulnerable to harms, both known and unknown.

What a manufacturer cannot do is market their supplements as a cure for any disease or medical condition. This doesn't mean the manufacturer can't suggest possible health benefits; many do. To better protect yourself, try to not be swayed by health claims that may or may not be true no matter how desperate you are for relief.

Because the quality and safety of kava can vary from one brand to the next, stick with manufacturers you know and trust. If also helps to buy brands certified organic under the regulations of the U.S. Department of Agriculture (USDA). This is especially true of wild-crafted dried kava.

Other Questions About Kava

How do I make kava tea or beverage?

Traditionally, kava drinks in the South Pacific are made from the fresh root, which is either chewed or pulverized before water is strained through the fibrous pulp.

Since fresh kava root is rarely available in the United States, you can make it make it with dried kava. For this, you would need a piece of cheesecloth, a tea strainer, and some wild-crafted kava chips or powder (usually found online or thorough specialty herbalist stores).

To make a 6- to 8-ounce glass of traditional kava drink:

  1. Put 1/4 to 1/3 cup of wild-crafted kava in a piece of cheesecloth. Tie it into a loose bundle with a piece of string .
  2. Heat one cup of water so that it is warm to the touch.
  3. Place the kava bundle in a small bowel and cover it with the warm water.
  4. Knead and squeeze the bundle for 10 to 15 minutes, applying a lot of pressure.
  5. When finished, pour the liquid through a tea strainer into a glass and drink.

Does kava give you a high?

Taken in normal doses, kava may help induce a sense of well-being and reduce feelings of anxiety. It does not necessarily produce a "high," but some people may experience pleasant feelings or a sense of calm and relaxation. Higher doses may produce a more significant effect but should be avoided due to the serious risk of liver damage.

What does kava do to the brain?

While kava's neurological effects are well-recognized, the exact mechanisms remain poorly understood. Some of the effects it has in the brain include the modulation of gamma-aminobutyric acid (GABA) receptors and the inhibition of monoamine oxidase B. Specific kava compounds may also affect dopamine, hippocampal neurons, and acetylcholinesterase,

Some research has also shown that kava may have neuroprotective effects.  

14 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. World Health Organization. Food and Agriculture Organization of the United Nations. Kava: A review of the safety of traditional and recreational beverage consumption: Technical Report.

  2. MedlinePlus. A guide to herbal remedies.

  3. Pittler MH, Ernst E. Kava extract for treating anxietyCochrane Database Syst Rev. 2002;(2):CD003383. doi:10.1002/14651858.CD003383

  4. Sarris J, LaPorte E, Schweitzer I. Kava: A Comprehensive Review of Efficacy, Safety, and Psychopharmacology. Aus N Z J Psychiatry. 2011;4(1):27-35. doi:10.3109/00048674.2010.522554.

  5. Sarris J, Stough C, Bousman CA, Wahid ZT, Murray G, Teschke R, Savage KM, Dowell A, Ng C, Schweitzer I. Kava in the treatment of generalized anxiety disorder: a double-blind, randomized, placebo-controlled study. J Clin Psychopharmacol. 2013;33(5):643-8. doi:10.1097/JCP.0b013e318291be67

  6. Lehrl S. Clinical efficacy of kava extract WS 1490 in sleep disturbances associated with anxiety disorders. Results of a multicenter, randomized, placebo-controlled, double-blind clinical trial. J Affect Disord. 2004;78(2):101-110. doi:10.1016/s0165-0327(02)00238-0

  7. Huck O, Han X, Mulhall H, Gumenchuk I, Cai B, Panek J, Iyer R, Amar S. Identification of a kavain analog with efficient anti-inflammatory effects. Sci Rep. 2019;9(1):12940. doi:10.1038/s41598-019-49383-8

  8. Shimoda LM, Park C, Stokes AJ, Gomes HH, Turner H. Pacific island 'Awa (Kava) extracts, but not isolated kavalactones, promote proinflammatory responses in model mast cells. Phytother Res. 2012;26(12):1934-41. doi:10.1002/ptr.4652

  9. Narayanapillai SC, Lin SH, Leitzman P, Upadhyaya P, Baglole CJ, Xing C. Dihydromethysticin (DHM) blocks tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced O6-methylguanine in a manner independent of the aryl hydrocarbon receptor (AhR) pathway in C57BL/6 female mice. Chem Res Toxicol. 2016;29(11):1828-1834. doi:10.1021/acs.chemrestox.6b00203.

  10. Bian T, Corral P, Wang Y, Botello J, Kingston R, Daniels T, Salloum RG, Johnston E, Huo Z, Lu J, Liu AC, Xing C. Kava as a clinical nutrient: Promises and challenges. Nutrients. 2020;12(10):3044. doi:10.3390/nu12103044

  11. National Center for Complementary and Integrative Health. Kava.

  12. Shinde P, Patil P, Bairagi V. Herbs in pregnancy and lactation: A review appraisal. Int J Pharm Sci Res. 2012;3(9):3001-3006. doi:10.13040/IJPSR.0975-8232.3(9).3001-06

  13. Cleveland Clinic. Kava Kava, Piper mesthystricum oral dosage forms.

  14. Tzeng YM, Lee MJ. Neuroprotective properties of kavalactones. Neural Regen Res. 2015;10(6):875-7. doi:10.4103/1673-5374.158335