Online sources of herbal product information.

Herbal products are commonly used to treat clinical conditions and are often purchased online without the supervision of a healthcare provider. The use of herbals remains controversial because of widespread exaggerated claims of clinical efficacy and safety. We conducted an online search of 13 common herbals (including black cohosh, echinacea, garlic, ginkgo, ginseng, green tea, kava, saw palmetto, and St John's wort) and reviewed the top 50 Web sites for each using a Google search. We analyzed clinical claims, warnings, and other safety information. A total of 1179 Web sites were examined. Less than 8% of retail sites provided information regarding potential adverse effects, drug interactions, and other safety information; only 10.5% recommended consultation with a healthcare professional. Less than 3% cited scientific literature to accompany their claims. Key safety information is still lacking from many online sources of herbal information. Certain nonretail site types may be more reliable, but physicians and other healthcare professionals should be aware of the variable quality of these sites to help patients make more informed decisions.