Researchers at the University of Queensland say Kava, used for generations in traditional Pacific ceremonies is an effective and safe treatment for anxiety.
Lead researcher, Jerome Sarris, says people with "chronic high levels of anxiety" feel less worried and, in some cases, less depressed during a 60-person trial.
He says they have been able to show that kava offers a natural alternative for the treatment of anxiety and, unlike some pharmaceutical options, has less risk of dependency and less potential of side-effects.
He also says they found that kava had a positive impact on reducing depression levels, something which had not been tested before.
Critically the study's participants did not show any signs of potential liver damage - contrary to concerns that prompted European, British and Canadian authorities to ban kava sales in 2002.
Mr Sarris says kava products sold in those countries were based on ethanol or acetone extracts of the kava plant and not the water-soluble extracts used traditionally by Pacific people and approved for sale in Australia.