New EU rules came into force at the weekend banning hundreds of herbal remedies. The laws are aimed at protecting consumers from potentially damaging "traditional" medicines.

Under the directive, herbal medicines will now have to be registered. Products must meet safety, quality and manufacturing standards, and come with information outlining possible side-effects.

Herbal practitioners and manufacturers say they fear the new rules could force them out of business.

Research conducted for the Medicines and Healthcare Products Regulatory Agency (MHRA) in 2009 showed that 26% of adults in the UK had taken a herbal medicine in the last two years, mostly bought over the counter in health food shops and pharmacies. Commonly used ingredients already registered include echinacea, which is used against colds, St John's wort, used for depression and anxiety, and valerian, which is claimed to ease insomnia.

The agency said it hoped to promote a more cautious approach to the use of herbal medicines after a study found that 58% of respondents believed these products were safe because they are "natural". In fact, herbal remedies can have harmful side-effects. St John's Wort can stop the contraceptive pill working, while ginkgo and ginseng are known to interfere with the blood-thinning drug warfarin. And in February the MHRA issued a warning about the herbal weight loss product Herbal Flos Lonicerae (Herbal Xenicol) Natural Weight Loss Formula, after tests showed it contained more than twice the prescribed dose of a banned substance.

To date, the industry has been covered by the 1968 Medicines Act, drawn up when only a handful of herbal remedies were available and the number of herbal practitioners was very small.

From now, manufacturers will have to prove their products have been made to strict standards and contain a consistent and clearly marked dose. Remedies already on sale will be allowed to stay on the shelves until their expiry date. The agency said there had been 211 applications for approval of herbal remedies so far, with 105 granted and the rest still under consideration. Approved remedies will come with a logo marked THR.