Actress Jenny Seagrove is spearheading a Conservative campaign to keep hundreds of vitamins and food supplements on the shelves in Britain.
Miss Seagrove challenged a legal ban on Kava-kava
The Tories say health remedies that have been used safely for years will disappear because of an EU Directive.
As part of their bid to save the supplements, Woman of Substance star Miss Seagrove is launching a petition to urge ministers to stop the EU ban.
The Tories claim this could be the last chance to change the EU legislation.
Health shop launch
The EU directive, to be enforced on 1 August 2005, is designed to harmonise the rules on vitamins and food supplements across the European Union.
It includes a list of vitamins and minerals which can be used in food supplements. It also includes upper limits on certain vitamins.
Groups opposed to the move say it will lead to many supplements disappearing off the shelves in Britain.
At lunchtime on Tuesday, stage and screen star Miss Seagrove will launch the nationwide e-petition at a health food shop in West London.
The petition, which can be found on the Conservative Party website, calls on ministers "to stop the EU from banning our vitamin and mineral supplements".
It also urges the government "to take action to secure a better deal for all British consumers of vitamin and mineral products".
Shadow health secretary Tim Yeo said he was delighted Miss Seagrove and the group Consumers for Health Choice were supporting the campaign.
"Labour let down millions of vitamins and food supplements' users when they passed the European Food Supplements Directive last year," he said.
An estimated 10m Britons take vitamin supplements
"When people discover that Labour is continuing to let them down, as they are not taking an active part in discussions over the details of the directive in Brussels, they will rightly be furious.
"This may be our last chance to change this unnecessary and damaging EU legislation.
"We hope that people will sign our e-petition and join us in our fight. With the public's help, we will do everything we can to force ministers to preserve access to these products on behalf of British consumers."
Earlier this year, opponents to the new EU rules on vitamins and food supplements won their fight to take the matter to the European Court of Justice.
The High Court in London ruled in January that their case could be referred to judges in Luxembourg.
Mr Justice Richards had been asked to refer the directive to the European Court on the grounds that it was unlawful and would unfairly affect millions of people, threatening both health and trade.