by Mary Curtis

Created on: March 05, 2009   Last Updated: March 26, 2009

A warm cup of St. John's wort tea before bedtime to help you sleep or a few capsules of echinacea to ward off a cold might seem like a good idea. But, if you are taking conventional medications, you may want to consult your doctor first to make sure these herbal preparations are helping and not hurting you.

Herbal products are not just old-fashioned and harmless, as some might think. In fact, new studies show that garlic, St. John's wort, echinacea, and other popular herbal products are actually as powerful as standard medicines and can interact, in harmful and even deadly ways, with other medications you are currently taking including even other-the-counter remedies such as pain kiillers.

Here is a list of popular herbals that were studied and their possible side effects or interactions with conventional medication:

* Garlic: Besides its use in cooking as a flavoring agent, garlic is popularly regarded for its ability to reduce cholesterol and atherosclerosis which is a buildup of plaque (fatty substance of which cholesterol is a component) inside the blood vessels.

A 2001 study done at the University of Vermont agreed that garlic can be used effectively. Even though results varied, garlic, they found, does decrease platelets cells which lead to the formation of blood clots and can therefore reduce plaque buildup. But this study warns that patients taking antiplatelet medication, including aspirin, run the risk of bleeding and myocardial infarction.

* St. John's Wort: This herb is popularly used as an anti-blue preparation because of it is commonly believed to relieve depression; it is also used as a sleep aid and to relax.

A German study concluded that St. John's wort is as effective as conventional treatment for moderate to severe depression but that results can vary because of lack of quality standard.

Two other studies conflict with each other over possible drug interaction. Dr. Aggarwal's study warns of problems with lidocaine, quinidine, amiodarone, cyclosporine, and calcium channel blockers. However, a University of Texas study found no indication of interference. The best thing to do is check with your doctor first if you are taking these or any cardiovascular medications.

* Echinacea: This herb can help strengthen the immune system because it contains flavonoids. It is this quality, however, that can interfere with an immunosuppressant such as cyclosporine. It can also cause tachycardia if you are taking amiodarone, propafenone, cyclosporine, or ibutilide.

* Gingko Biloba: Trial data shows that this herb can help dementia but if you are taking aspirin or anticoagulants, do not take gingko biloba.

* Ginseng: Used as a tonic, you should know that ginseng raises blood pressure. Don't use it if you are taking warfarin, heparin, or aspirin.

Sources:

1. Dr. Atul Aggarwal, Department of Medicine, University of Vermont, Burlington, Vermont, USA, 6/26/2001 (http://health.burlingtonfreepress.com/TextItem.aspx? id=2139.

2. Dasqupta, Tso, Szelei-Stevens, University of Texas-Houston Medical School, Houston, Texas, USA, 3/18/2005 (http://cat.inist.fr/?aModele=afficheN&cpsidt=17638659.

3. Meinhard Kieser, Dr. Willmar Schwabe Pharmaceuticals, Karlsruhe, Germany, 2/11/2005(http://www.psychtreatment.com/st.john's_wort.htm.

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