Supplement Forms/Alternate Names:

Piper methysticum, kava kava, ava pepper, ava root, kawa


Kava is a plant in the pepper family. The roots and stems are made into a traditional drink from the Pacific Islands known as Kava. It has been used to ease feelings of anxiety and depression. Kava can be taken as a pill, powder, or extract. It can also be made into tea.


120 to 240 milligrams once daily

What Research Shows

May Be Effective

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It may not be safe to take kava for a short or long period of time. Drying and yellowing of the skin and liver failure may happen. Kava should not be used during pregnancy or breastfeeding.D1-D7


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse, such as:

  • Kava should not be taken 24 hours before surgery. It has a sedative effect.
  • People taking blood thinners should talk to their doctors before taking kava. It may increase the risk of bleeding.
  • People taking antidepressants, medicine to relax the muscles, pain pills, or anxiety medicine should talk to their doctor before taking kava. It may overwhelm the body’s central nervous system.
  • People with schizophrenia or other mental health problems should talk to their doctor before taking kava. It may interact with their medicines.


A. Anxiety

A1. Sarris J, Kavanagh DJ, et al. The Kava Anxiety Depression Spectrum Study (KADSS): a randomized, placebo-controlled crossover trial using an aqueous extract of Piper methysticum. Psychopharmacology (Berl). 2009;205(3):399-407.

A2. Lakhan SE, Vieira KF. Nutritional and herbal supplements for anxiety and anxiety-related disorders: systematic review. Nutr J. 2010;7(9):42.

A3. Sarris J, Scholey A, et al. The acute effects of kava and oxazepam on anxiety, mood, neurocognition; and genetic correlates: a randomized, placebo-controlled, double-blind study. Hum Psychopharmacol. 2012 May;27(3):262-269.

A4. Sarris J, Stough C, et al. Kava for the treatment of generalized anxiety disorder RCT: analysis of adverse reactions, liver function, addiction, and sexual effects. Phytother Res. 2013;27(11):1723-1728.

A5. Sarris J, Stough C, et al. Kava in the treatment of generalized anxiety disorder: a double-blind, randomized, placebo-controlled study. J Clin Psychopharmacol. 2013;33(5):643-648.

A6. Ooi SL, Henderson P, Pak SC. Kava for Generalized Anxiety Disorder: A Review of Current Evidence. J Altern Complement Med. 2018 Aug;24(8):770-780.

A7. Smith K, Leiras C. The effectiveness and safety of Kava Kava for treating anxiety symptoms: A systematic review and analysis of randomized clinical trials. Complement Ther Clin Pract. 2018 Nov;33:107-117.

B. Attention Deficit Hyperactivity Disorder

B1. Sarris J, Kean J, et al. Complementary medicines (herbal and nutritional products) in the treatment of Attention Deficit Hyperactivity Disorder (ADHD): a systematic review of the evidence. Complement Ther Med. 2011 Aug;19(4):216-227.

C. Insomnia

C1. Leach MJ, Page AT. Herbal medicine for insomnia: A systematic review and meta-analysis. Sleep Med Rev. 2015 Dec;24:1-12.

D. Safety

D1. Teschke R. Kava hepatotoxicity--a clinical review. Ann Hepatol. 2010 Jul-Sep;9(3):251-265.

D2. Sarris J, LaPorte E, et al. Kava: a comprehensive review of efficacy, safety, and psychopharmacology. Aust N Z J Psychiatry. 2011;45(1): 27-35.

D3. Teschke R, Wolff A, et al. Herbal hepatotoxicity: a tabular compilation of reported cases. Liver Int. 2012 Nov;32(10):1543-1556.

D4. Bunchorntavakul C, Reddy KR. Review article: herbal and dietary supplement hepatotoxicity. Aliment Pharmacol Ther. 2013 Jan;37(1):3-17.

D5. Fasinu PS, Gurley BJ, et al. Clinically Relevant Pharmacokinetic Herb-drug Interactions in Antiretroviral Therapy. Curr Drug Metab. 2015;17(1):52-64.

D6. Stickel F, Shouval D. Hepatotoxicity of herbal and dietary supplements: an update. Arch Toxicol. 2015 Jun;89(6):851-65. doi: 10.1007/s00204-015-1471-1473.

D7. Brown AC. Liver toxicity related to herbs and dietary supplements: Online table of case reports. Part 2 of 5 series. Food Chem Toxicol. 2017 Sep;107(Pt A):472-501.

Last reviewed February 2020 by EBSCO NAT Review Board Eric Hurwitz, DC

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