The study, published in the World Journal of Gastroenterology, used an electron microscope to determine how one key ingredient in kava -- kavain -- affected liver cells.
The study found the liver tissue displayed an overall change in structure, including the narrowing of blood vessels, the constriction of vessel passages and retraction of the cellular lining following kavain treatment. Kavain also adversely affected the liver as part of the body's immune system.
Bottom line: The kavain treatment disturbed the basic structure of the liver, which may seriously impact normal liver function, the researchers said in a statement released by the University of Sydney.
The study supports "earlier literature observations on kava's adverse affects on the functioning of the liver in general."
The research team was led by Iqbal Ramzan of the University of Sydney, who is originally from Fiji, where drinking kava is common.
Kava, as a beverage, is primarily consumed to relax, but in some parts of the world, kava extract is marketed as herbal medicine against stress, insomnia and anxiety.