The UK's medicines regulatory body is reviewing the ban on the herbal, brought into force in January 2003 after kava was linked to a number of deaths and liver damage around the world.
The industry has repeatedly argued that these deaths could have been caused by factors other than kava but it could not stop kava products from being removed from all major European and North American markets.
The Medicines and Healthcare products Regulatory Agency (MHRA), which has opened the review process as planned after a two-year ban, says that the existing evidence and the independent expert advice previously received offers no support for a lifting of the ban but that it will consider any new evidence.
It added that it has also become aware of additional cases of liver toxicity, suspected to be associated with the use of kava-containing products, since it first consulted on proposals to ban the herbal in July 2002.
Joerg Gruenwald of Phytopharm Consulting who has been lobbying for kava's reintroduction into Europe, believes that new toxicology studies being carried out in Germany could be enough to reverse the law.
"The cell culture study is finished and has shown no toxicity in any relevant dosages," he told NutraIngredients.com.
This data, along with other unpublished trials, will be submitted to MHRA. A further toxicology study on rats is unlikely to be completed by the review deadline but could influence future legislation, he added.
"The study protocols were agreed on by the German health authorities. That is internationally relevant," he added.
The German market, previously the biggest for kava, could be tougher to regain as the authorities are also calling for a human clinical trial. According to Gruenwald, this should not be relevant as issues over the herbal have all been related to safety rather than efficacy.