Herbal medicines are used by many people, who naively believe that just because they are natural there safe. Many products however, have potentially dangerous interactions with other medications and can have similar side effects to conventional drugs. A new study published in BioMed Centrals open access journal BMC Medicine shows key information required for safe use is not contained on several over-the-counter herbal products.

Although the image for herbal products looks healthy, a third of users are totally oblivious to any risks, despite many products having adverse effects. Investigators from the University of Leeds brought 68 different preparations of five most commonly used remedies (St Johns wort, Asian ginseng, Echinacea, garlic and Ginkgo) at two popular health food stores, three large chain pharmacies and three supermarket pharmacies. Safety information supplied by the US National Center for Complementary and Alternative Medicine was compared against the information provided with the products investigators bought, and was analyzed for completeness and accuracy regarding precautions, interactions with other drugs, and side effects.

Each of the products selected are known to have potentially harmful effects to some people. The contraceptive pills effectiveness can be reduced by St Johns wort, and can also affect warfarin, which is taken to prevent blood clotting. Ginkgo and Echinacea can cause allergic reactions while Asian ginseng is not suitable for those with diabetes. Garlic can also cause problems for some people because it can thin blood and interfere with the drugs used to treat HIV. Investigators discovered that a staggering 93% of the products analyzed were unlicensed, and consequently not required to meet any standard of safety or quality, with half being marketed as food supplements. Only 13% of products contained an information sheet and only three contained an acceptable amount of safety information.

Professor Theo Raynor explained,

“Consumers need reliable and comprehensive information when buying herbal remedies information which tells them whether the remedy is suitable for them.

From April 2011 an EU directive requires herbal medicinal products to be licensed, or to get Traditional Herbal Registration (THR), which means the information with the product has been approved.

This applies to things like St Johns wort and Echinacea, but not necessarily to others such as Asian ginseng and ginkgo. It also does not apply to existing stock, which can still be sold off. People should look out for the THR logo when buying these products. Furthermore pharmacists and doctors need to be made aware what herbal remedies people are taking so that their patients receive the best possible care.”

Written by Grace Rattue