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August 2013

Kava Safety and Effectiveness Reviewed For Anxiety

Kava may be more effective for the treatment of anxiety compared to placebo, according to a study.

Kava beverages, made from dried roots of the shrub Piper methysticum, have been used ceremonially and socially in the South Pacific for hundreds of years and in Europe since the 1700s. Several well-conducted human studies have demonstrated kava's efficacy in the treatment of anxiety with effects observed after as few as one to two doses and progressive improvements over one to four weeks.

There is growing concern regarding the potential for liver toxicity from kava. Multiple cases of liver damage have been reported in Europe, including hepatitis, cirrhosis, and liver failure. Kava has been removed from shelves in several countries due to these safety concerns. The U.S. Food and Drug Administration (FDA) has issued warnings to consumers and physicians. It is not clear what dose or duration of use is correlated with the risk of liver damage. The quality of these case reports has been variable; several are vague, describe use of products that do not actually list kava as an ingredient, or include patients who also ingest large quantities of alcohol. Nonetheless, caution is warranted. Chronic or heavy use of kava has also been associated with cases of neurotoxicity, pulmonary hypertension, and dermatologic changes.

Scientists reviewed clinical trials that evaluated the safety and effectiveness of kava for anxiety. They included seven trials in their analysis that compared kava to a placebo treatment in people with anxiety, and excluded any studies that evaluated kava as part of a combination treatment in order to determine the effects of kava alone.

All of the studies reviewed found results suggesting that kava extract may be more effective compared to placebo. The trials reported mild, short-lived, and infrequent side effects as a result of using kava.

The reviewers concluded that this evidence may support the effectiveness of kava for the treatment of anxiety, compared to placebo. More research is needed to confirm these results, as well as to further determine the safety and effectiveness of kava for this condition.

In addition to kava, numerous other integrative therapies have been evaluated for anxiety and related conditions. There is strong scientific evidence supporting the use of music therapy for anxiety.

For more information about kava, please visit Natural Standard's Foods, Herbs & Supplements Database.


  1. Natural Standard: The Authority on Integrative Medicine. 
  2. Pittler MH, Ernst E. Kava extract for treating anxiety. Cochrane Database Syst Rev. 2002;(2):CD003383. 

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