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Can kava help ease anxiety, and is it safe for the liver?

Some short trials found kava eased anxiety more than placebo. The largest recent trial did not, and liver safety needs care.

Published October 2026

Short answer

Some short trials show kava can ease anxiety, but the newest large trial found no benefit and liver injury has been reported. Evidence grade C (Limited). Several randomized trials and two pooled reviews; downgraded for inconsistency and a small total sample.

Key takeaways

  • In some short trials, kava reduced anxiety more than placebo; pooled across five trials of 330 people, more people responded to kava [1].
  • The largest recent trial, 171 adults followed for 16 weeks, found no significant benefit over placebo [2].
  • Kava has been linked to liver injury in case reports, so people with liver disease or on other medicines should check with a doctor first [3][4].
  • Most trials used a standardized root extract, so results may not apply to every kava product [2].

The short version

In some short trials, people taking kava reported less anxiety than people on placebo, and a pooled analysis favored kava [1]. The results conflict, though. The largest recent trial found no clear benefit [2], and liver injury has been reported in people who use kava [3].

What the studies show

Pooled results. A 2018 review found kava beat placebo in 3 of 7 placebo-controlled trials. Five trials with 330 people gave a pooled risk ratio of 1.50 (95% CI 1.12 to 2.01) for people who responded to treatment [1].

Smaller meta-analyses. Three placebo-controlled trials with 130 people gave effect sizes between 0.59 and 0.99 in favor of kava, but these did not reach statistical significance [5]. A 2018 network analysis estimated kava lowered Hamilton anxiety scores by about 3.2 points more than placebo, which was not statistically significant [6]. A 2022 network analysis of 29 trials of herbs found kava lowered anxiety scores by about 2.5 points, but its authors said kava may not work in generalized anxiety disorder specifically [7].

Individual trials. A 2013 trial of 58 adults with generalized anxiety disorder found kava reduced anxiety more than placebo. Remission was 26% on kava and 6% on placebo [8]. A larger 2020 trial of 171 adults over 16 weeks found no significant difference: remission was 17% on kava and 24% on placebo [2]. A 4-week trial of 37 people found no difference from placebo [9]. A 2003 trial of 127 people found kava extract LI 150 worked about as well as buspirone and opipramol, but it had no placebo group [10]. In a crossover trial of 22 moderately anxious adults, one dose of kava did not reduce anxiety, while oxazepam did [11].

The nuances

The product matters. Most trials used a standardized aqueous root extract giving 120 to 240 mg of kavalactones a day [8][2]. Results may not carry over to other kava drinks or products. Trials mostly ran 4 to 16 weeks [9][2].

Earlier reviews were more upbeat. A 2010 review of 24 studies called the evidence for kava strong, but it could not pool the results because the trials were few and varied [12]. A 2007 analysis of 21 anxiety drug trials found complementary treatments, kava among them, did worse than placebo on average [13].

Liver. Kava is among the herbs most often linked to liver injury in case reports. A review of herb-related liver injury counted 936 cases across all herbs; liver transplant was needed in 6.6% of them [3]. In trials, liver tests were mostly unchanged. A 16-week trial found abnormal liver tests more often on kava, but no one met the criteria for liver injury [2]. A 6-week trial found no liver test differences [14]. A 2018 review warned that liver toxicity is especially possible with use beyond 8 weeks [1].

Medicines. In 12 healthy people, 28 days of kava cut the activity of one liver enzyme (CYP2E1) by about 40% [15]. A review lists possible interactions with alprazolam, levodopa and paroxetine [4], and a possible interaction with benzodiazepines has been reported [16]. Another review said true interactions remain unconfirmed [17].

Brain and gene studies are early. A brain-scan study of 37 people found kava lowered GABA in one brain area, which fits a calming effect but does not show it helps symptoms [18]. One author of that study reports payments from MediHerb, a kava product maker [18].

What this means for you

The trials are too mixed to say kava reliably eases anxiety. Its liver and drug-interaction risks matter most for people with liver disease, people taking other medicines, and anyone who is pregnant [3][4][19]. Kava is not a substitute for medical care for an anxiety disorder. Talk with a doctor before trying it.

Go deeper

  • Kava — Kava may ease anxiety for a few weeks: several short trials favored it over placebo, but the largest recent trial found no benefit.

References

  1. 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.
  2. Kava for generalised anxiety disorder: A 16-week double-blind, randomised, placebo-controlled study.. Aust N Z J Psychiatry, 2020.
  3. Herb-induced liver injury: Systematic review and meta-analysis.. World J Clin Cases, 2021.
  4. Interactions between herbal medicines and prescribed drugs: an updated systematic review.. Drugs, 2009.
  5. Kava for Generalized Anxiety Disorder: A Review of Current Evidence.. J Altern Complement Med, 2018.
  6. Complementary and Alternative Medicine Treatments for Generalized Anxiety Disorder: Systematic Review and Meta-analysis of Randomized Controlled Trials.. Adv Ther, 2018.
  7. Medicinal herbs for the treatment of anxiety: A systematic review and network meta-analysis.. Pharmacol Res, 2022.
  8. Kava in the treatment of generalized anxiety disorder: a double-blind, randomized, placebo-controlled study.. J Clin Psychopharmacol, 2013.
  9. A placebo-controlled study of Kava kava in generalized anxiety disorder.. Int Clin Psychopharmacol, 2002.
  10. Kava-Kava extract LI 150 is as effective as Opipramol and Buspirone in Generalised Anxiety Disorder--an 8-week randomized, double-blind multi-centre clinical trial in 129 out-patients.. Phytomedicine, 2003.
  11. The acute effects of kava and oxazepam on anxiety, mood, neurocognition; and genetic correlates: a randomized, placebo-controlled, double-blind study.. Hum Psychopharmacol, 2012.
  12. Nutritional and herbal supplements for anxiety and anxiety-related disorders: systematic review.. Nutr J, 2010.
  13. An effect-size analysis of pharmacologic treatments for generalized anxiety disorder.. J Psychopharmacol, 2007.
  14. Kava for the treatment of generalized anxiety disorder RCT: analysis of adverse reactions, liver function, addiction, and sexual effects.. Phytother Res, 2013.
  15. In vivo effects of goldenseal, kava kava, black cohosh, and valerian on human cytochrome P450 1A2, 2D6, 2E1, and 3A4/5 phenotypes.. Clin Pharmacol Ther, 2005.
  16. A systematic review of the safety of kava extract in the treatment of anxiety.. Drug Saf, 2002.
  17. Pharmacokinetic and pharmacodynamic drug interactions with Kava (Piper methysticum Forst. f.).. J Ethnopharmacol, 2004.
  18. Neuroimaging Insights: Kava's (Piper methysticum) Effect on Dorsal Anterior Cingulate Cortex GABA in Generalized Anxiety Disorder.. Nutrients, 2023.
  19. Neonatal and Maternal Ichthyosiform Dermopathy in Association with Kava Use during Pregnancy.. J Med Toxicol, 2024.