Kava-kava: a lesson for the phytomedicine community.

The recent widespread prohibition of kava-kava (“kava”, Piper methysticum) has raised fundamental questions about the regulation of herbal medicines. A remedy with established efficacy and long standing popularity has been withdrawn, with severe damage to the economies of several small Pacific nations, on the basis of uncertain reports linking its consumption to liver damage. No rigorous assessment of the balance of benefit and risk has been produced in support of these measures, nor are there opportunities for a reappraisal of its value in human subjects. The world of phytomedicine has been caught unprepared. Are there lessons to be learnt to avoid such events in the future?