Systematic reviews of complementary therapies – an annotated bibliography. Part 2: Herbal medicine
1 Centre for Complementary Medicine Research, Department of Internal Medicine II, Technische Universität, München, Kaiserstr. 9, 80801 München, Germany
2 Institute for Social Medicine & Epidemiology, Charité Hospital, Humboldt University, Berlin, Germany
3 HS Centre for Reviews & Dissemination, University of York, UK
4 Department of Epidemiology, Maastricht University, The Netherlands
5 Consortial Center for Chiropractic Research, Davenport, Iowa, USA
6 Memorial Sloan-Kettering Cancer Center, New York, USA
7 Division of Complementary Medicine Department of Internal Medicine, Universitätsspital Zurich, Switzerland
BMC Complementary and Alternative Medicine 2001, 1:5 doi:10.1186/1472-6882-1-5Published: 20 July 2001
Complementary therapies are widespread but controversial. We aim to provide a comprehensive collection and a summary of systematic reviews of clinical trials in three major complementary therapies (acupuncture, herbal medicine, homeopathy). This article is dealing with herbal medicine. Potentially relevant reviews were searched through the register of the Cochrane Complementary Medicine Field, the Cochrane Library, Medline, and bibliographies of articles and books. To be included articles had to review prospective clinical trials of herbal medicines; had to describe review methods explicitly; had to be published; and had to focus on treatment effects. Information on conditions, interventions, methods, results and conclusions was extracted using a pre-tested form and summarized descriptively.
From a total of 79 potentially relevant reviews pre-selected in the screening process 58 met the inclusion criteria. Thirty of the reports reviewed ginkgo (for dementia, intermittent claudication, tinnitus, and macular degeneration), hypericum (for depression) or garlic preparations (for cardiovascular risk factors and lower limb atherosclerosis). The quality of primary studies was criticized in the majority of the reviews. Most reviews judged the available evidence as promising but definitive conclusions were rarely possible.
Systematic reviews are available on a broad range of herbal preparations prescribed for defined conditions. There is very little evidence on the effectiveness of herbalism as practised by specialist herbalists who combine herbs and use unconventional diagnosis.