Many herbal remedies available over-the-counter in pharmacies and health food shops are still lacking important information needed for safe use, according to University of Leeds researchers.
In April this year, a new EU law came into force regulating the sale of traditional herbal medicines, such as St John's wort and Echinacea.
These products must now contain clear information on possible side effects, how they could interact with other prescribed medicines and whether people with existing illnesses should take them or not. They are clearly marked with the THR logo showing they have 'Traditional Herbal Registration'.
However, a number of popular herbal remedies, such as Asian ginseng and ginkgo, may not be covered by this law and could be missing key details on their safe use.
Also, existing stocks on the shelves of shops and pharmacies, produced before the law came into force, can still be bought and will not have the new clear safety information.
An investigation by University of Leeds researchers, published in BioMed Central's open access journal BMC Medicine, revealed that prior to April 2011, the majority of over-the-counter herbal products did not contain any of the key information required for safe use.
But despite the change in the law, there is no guarantee that the situation will be radically different now, according to Professor of Pharmacy Theo Raynor, who led the study.
"The best advice to consumers is 'buyer beware', as it always has been," said Professor Raynor. "Many people believe herbal medicines are somehow different to other medicines because they are 'natural'. However, any substance that affects the body - no matter where it came from - has the potential to do harm if it is not taken correctly."
During the investigation, the University of Leeds researchers bought 68 different preparations of five commonly used remedies (St John's wort, Asian ginseng, Echinacea, garlic and Ginkgo) at two well known health food stores, three large chain pharmacies, and three pharmacies at supermarkets. All of the products are known to have potentially harmful effects for some people.
St John's wort can reduce the effectiveness of the contraceptive pill and Ginkgo can increase the risk of bleeding. Asian ginseng is not suitable for people with diabetes and Echinacea can cause allergic reactions. Even garlic can cause problems for some people because it can thin the blood and interfere with drugs used to treat HIV.
The information provided with these products was compared to safety information, provided by the US National Center for Complementary and Alternative Medicine, and was evaluated for completeness and accuracy regarding precautions, interactions with other drugs, and side effects.
The researchers found that 93% of the products evaluated were unlicensed, and consequently not required to meet any standard of safety information provision, and over half of these were marketed as food supplements. Only 13% contained an information sheet and only three contained an acceptable amount of safety information.
"Consumers need reliable and comprehensive information when buying herbal medicines - information which tells them whether it is suitable for them," Professor Raynor said. "I would advise anyone buying a herbal medicine to check that the box or packaging contains the 'THR' logo, which shows that the information it comes with has been approved.
"Herbal medicines should, ideally, be purchased where trained staff are available, so that consumers can have any questions answered. This information should be available from pharmacists. People should also always tell their doctor about herbal medicines they are taking, so they receive the best possible care."
For further information:
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Buyer beware? Does the information provided with herbal products available over the counter enable safe use? David K Raynor, Rebecca Dickinson, Peter Knapp, Andrew F Long and Donald Nicolson. BMC Medicine