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Kava-kava: Bans to be Reconsidered.







 Copyright © Cropwatch June 2005




Brief summary.

Root preparations from the Pacific Island plant kava-kava (Piper methysticum G. Forster) are used in ceremonial and social contexts in the Pacific Islands; Siegel (1989) has described the plant as a sedative hypnotic. Herbal medicinal preparations of kava became immensely popular in the West during the 1990’s, to treat anxiety, insomnia and muscular pain. Plant parts are also used as food products, for example to make an infused tea. Yarnell & Abscal (2002) have previously listed Piper methysticum (Kava-kava) under “Potentially Unsustainable or Definitely Endangered Botanicals” whilst referring to its’ extensive cultivation in small plots on the Pacific Islands. This is slightly at variance with an earlier WWF article which maintained the plant is not threatened but subject to boom-bust market forces leading to periodic shortages – see

The action of kava does not depend on single actives but the combination of several kavalactones to produce a synergistic physiological effect (Lebot et al. 1997). These include components such as kavain, dihydrokavain, yangonin, demethoxy-yangonin, methysticin and dihydromethysticin. Eleven chemotypes of kava, their distribution and the chemical identification and characterisation of active principles associated with kava’s various physiological activities are comprehensively accounted by Lebot et al. 



Following concerns that some (rare) cases of liver damage (cirrhosis, hepatitis) were associated with its use, the German & Swiss Health Authorities made a superficial inquiry which was eventually followed by a ban in Germany, which was immediately copied by seven other countries including Canada. In the UK, the Medicines Control Agency (MCA) had called for a voluntary ban on kava-kava in mid 2002, and subsequently opinions were sought from the Committee of Safety of Medicines (CSM) and the Medicines Commission, on the safety of kava-kava medicinal preparations. Both the MCA & MC found evidence of risk in rare cases and advised that kava-kava should be prohibited from sale to protect public health. The Food Standards Agency reviewed the same evidence, and continues to advise consumers not to eat products containing kava-kava, which it has done since Dec 2001. Subsequently the kava kava in Food (England) Regulations 2002 came into force on 13 January 2003.


Serious Criticisms of the MCA’s Opinion on Kava.

There have been various criticisms of the MCA’s review and subsequent actions. The National Institute of Medicinal Herbalists (NIMH) in a press release in 2002, accused the MCA of ignoring their submitted evidence, and ‘banning the wrong thing’ by confusing the safe traditional herbal usage with commercial ‘over the counter’ concentrated extracts, and further made criticism of the evidence presented to the BfArm (the German equivalent to the MCA). Hasselberger (2003) later related that the problem of liver toxicity is connected to the practice by some European extractors of using the kava stem bark peelings which are never used by traditional kava drinkers. These peelings contain the alkaloid pipermethystine which initial studies show a negative effect on liver cell cultures. Smith (1979) had first identified this alkaloid in kava leaves.


Whitton et al. (2003) take a similar line to the NIMH position and confirm kava-kava’s safe use as a beverage over several centuries. In contrast the authors maintain that the preparation of standardised extracts by via acetone extraction has caused negative health effects (even death) and discuss possible reasons for this, which centre around the involvement of gluathione . In reviewing the evidence to date in Jan 2003, Clouatre (2003) remarked that “the risk-to-benefit ratio of kava extracts, nevertheless, remains good in comparison with that of other drugs used to treat anxiety.” Ernst (2003) speaking at a symposium organised by Exeter & Plymouth Universities, has been reported (Eickmeier 2003) to complain that the MCA failed to carry out a proper risk-benefit analysis, that kava-kava was as effective as benzodiazopines to treat anxiety, and quoted figures showing 0.008 adverse effects per million doses for kava-kava against 2.12 adverse effects per million doses for Valium. A comprehensive update on the European kava-kava situation has been written by Ernst (Ernst 2004). 


The actress Jenny Seagrove and the National Association of Health Stores famously took the Secretary of State for Health UK Govt. to court over the issue in November 2003, and lost. However the National Assembly of Wales successfully reversed the 2002 ban decision, which came into force in October 2003. The WHO (Oct 2003) announced that it was re-evaluating its position on kava-kava. Gruenwald (2004) reported that an international group is seeking to persuade governments to reconsider their position on kava, and that the MCA in the UK is due to do this in 2005.


Below is a communiqué from Gruenwald, who is Executive Director of the International Kava Executive Council (reproduced by his kind permission).


“German Kava discussion re-opened

By letter of May 12, 2005, the German health authorities finally decided on the appeal of kava producers against the ban of German registered kava drug products of 2002. The kava ban was revoked, as the German BfArM itself stated, “for reasons of appropriateness”.


The decision to revoke the cancellation of drug registrations does, however, not mean that kava is again available on the markets. The registrations in question are inactivated until further notice. The decision to temporarily inactivate kava registrations was based on a risk-benefit evaluation, where the BfArM came to the conclusion of a lack of proofs of anxiolytic efficacy of kava products, with all existing studies either performed with higher than registered dosage schemes, in different indications, or otherwise with a non-controlled study design. The producers were asked to provide new clinical data until June, 2007, in which case a re-institution of the kava products on the market might again be possible.


The International Kava Executive Council, which presents the interests of the South Pacific kava producing countries in a fair evaluation of kava risks based on a scientific discussion of facts, has been working hard to provide new data to underline the inappropriateness of the kava ban. A tremendous mass of positive scientific evidence on kava safety was assembled by international scientists, and presented on the occasion of the International Kava Conference in Suva, Fiji, in December 2004.


“We believe that the new scientific evidence and the constant political background work of the governments of the South Pacific states contributed to this new development”, said Dr. Joerg Gruenwald, Executive Director of the IKEC. The new decision is of course not the end of the story, mainly because there does not seem to be a change for the situation of the consumers and physicians. When kava was banned, the withdrawal of the products from the market created a distinct gap in the therapeutic arsenal of the physicians for the treatment of mild to moderate stress and anxiety related disorders. With the new decision, kava is still not made available to therapy. “Despite kava not being put back on the shelves for now, the decision is still a milestone, as now the administrative way to regular kava registrations is again open”, explained the kava scientist Dr. Mathias Schmidt from the IKEC. Only a few days ago, an application would not even have been considered for the registration process. “We are glad that the discussion is now re-opened, and we hope to finally come to a constructive dialogue with the BfArM”.


The question of efficacy of kava is still a matter of debate. Among scientists, there is no question that kava is efficacious, and that the quantity and quality of clinical evidence is high enough to prove efficacy. This, however, reflects the general picture. Gruenwald: “The doubts raised by the BfArM do not concern efficacy of kava as such, but of individual products, based on technical flaws in published data.” The offer to re-evaluate the risk-benefit ratio based on valid new clinical data shifts the focus from toxicity to efficacy. If proper clinical evidence of efficacy is enough to overcome the current unavailability of kava products, the dangers from potential kava toxicity finally seem to be regarded as acceptable. Scientists always pointed to the fact that kava toxicity – if existing – occurred in an extremely low number of patients, by far below the incidence rates observed with many other freely available drugs. The kava drug producers will now discuss the possible ways forward, and evaluate the chances to provide data from a new and state of the art clinical trial.”


*Note: A personal communiqué from Prof Ernst (10.07.05) points out that he is a member of the 'Medicines Commission' of the MCA (now MHRA) where the final judgement on kava was taken - which perhaps makes the MCA's collective decision even more incomprehensible. Prof. Ernst also stated that a re-evaluation is in the pipeline, but wasn't able to state when this would happen.




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Clouatre D.L. (2003) “Kava kava: examining new reports of toxicity” Toxicology Letters 150(1), 85-96.


Eickmeier J. (2003) “Is kava more dangerous than valium?” – see,5778,s1-1-52-125-2649-1,00.html


Ernst E. (2004) “Kava Update: A European Perspective” J. New Zealand Medical Assocn. 117, No. 1205, full text available at


Gruenwald J. (2004) “Kava Stakeholders Plan Regulatory Review and Market Return.” HerbalGram (2004) No 61: 69-70.


Hassleberger, Sepp (2003) – see and other kava articles on this website.


Siegel R.K. (1989) Intoxication: Life in Pursuit of an Artificial Paradise pub. E.P. Dutton, New York, 1989.


Smith R.M. Pipermethystine: a Novel Pyridone Alkaloid from Piper methysticum (cultivated in the South Pacific as a Drug and a Beverage Plant). Tetrahedron Letters 5, 437-439.


Whitton P.A., Lau A., Salisbury A., Whitehouse J,, & Evans C.S. (2003) Phytochemistry 64(3), 673-679.


Yarnell E. & Abascal K. (2002) “Dilemmas of Traditional Botanical Research” Herbalgram 55, 46-55. 



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Further reading:

Lebot V., Merlin M. & Lindstrom L. (1997) Kava: The Pacific Elixir Healing Arts Press, Rochester Vermont.


Singh, Yadhu N. (2004) Kava: from Ethnology to Ethnopharmacology CRC Press Boca Raton, Fl. (2004).


The information supplied in this bulletin is believed to be accurate, but views, comments, criticisms, corrections or additional material can be forwarded to for consideration in future communiqués in the Cropwatch series.