Kava hepatotoxicity: Comparison of aqueous, ethanolic, acetonic kava extracts and kava–herbs mixtures

Ethnopharmacological relevanceEthanolic and acetonic kava extracts have previously been causally related to rare hepatotoxicity observed in patients from Germany and Switzerland, but causality assessment was not performed in cases of patients having taken the traditional aqueous kava extracts of South Pacific islands or kava–herbs mixtures.Aim of the studyTo study the possible hepatotoxicity of aqueous kava extracts of the South Pacific Islands.Materials and methodsCausality of hepatotoxicity by aqueous kava extracts and kava–herbs mixtures was assessed, using the updated score of the quantitative CIOMS (Council for the International Organizations of Medical Sciences).ResultsCausality was established in five patients from New Caledonia, Australia, the United States and Germany for aqueous kava extracts and kava–herbs mixtures. A comparison with 9 patients from Germany and Switzerland with established causality of hepatotoxicity by ethanolic and acetonic kava extracts reveals that the clinical picture in all 14 patients is similar, independently whether aqueous, ethanolic and acetonic kava extracts or kava–herbs mixtures were used.ConclusionsKava hepatotoxicity occurs also with traditional aqueous kava extracts of the South Pacific islands and thereby independently from ethanol or acetone as chemical solvents, suggesting that the toxicity is linked to the kava plant itself with a possibly low quality of the used kava cultivar or kava plant part rather than to chemical solvents.