The European Court of Justice is about to rule on whether the EU Food supplements directive, due to come into effect in August, unlawfully infringes trade.
This means in effect that an earlier European directive tightening rules on the sale of vitamins and food supplements, could be overturned.
As it stands, the ruling would mean supplements, which could include vitamins and minerals, would only be available if on an approved list and limits would be placed on upper doses for vitamins.
Obviously health food suppliers are up in arms and say it threatens the sale of as many as 5,000 products.
The original directive was approved by EU governments in 2002 and was designed to tighten controls on the growing market in products sold under the health food heading such as natural remedies, vitamin supplements and mineral plant extracts.
Three major health food organisations in the UK, the Alliance for Natural Health (ANH), the Health Food Manufacturers' Association (HFMA) and the National Association of Health Stores (NAHS) all oppose the plans.
They argue that the legislation is too restrictive, and will threaten thousands of perfectly safe products, containing more than 200 nutrients not on the approved list.
Back in April, the European Court of Justice Advocate General, Leendert Geelhoed, said, after reviewing the evidence presented by both sides, that in his opinion, the directive infringed legal guidelines.
If the appeal is upheld it will be only the fourth time an EU directive has been thrown out.