An evaluation of selected herbal reference texts and comparison to published reports of adverse herbal events.
OBJECTIVE
There has been a recent proliferation of medical reference texts intended to guide practitioners whose patients use herbal therapies. We systematically assessed six herbal reference texts to evaluate the information they contain on herbal toxicity.


METHODS
We selected six major herbal references published from 1996 to 2000 to evaluate the adequacy of their toxicological information in light of published adverse events. To identify herbs most relevant to toxicology, we reviewed herbal-related calls to our regional California Poison Control System, San Francisco division (CPCS-SF) in 1998 and identified the 12 herbs (defined as botanical dietary supplements) most frequently involved in these CPCS-SF referrals. We searched Medline (1966 to 2000) to identify published reports of adverse effects potentially related to these same 12 herbs. We scored each herbal reference text on the basis of information inclusiveness for the target 12 herbs, with a maximal overall score of 3.


RESULTS
The herbs, identified on the basis of CPCS-SF call frequency were: St John's wort, ma huang, echinacea, guarana, ginkgo, ginseng, valerian, tea tree oil, goldenseal, arnica, yohimbe and kava kava. The overall herbal reference scores ranged from 2.2 to 0.4 (median 1.1). The Natural Medicines Comprehensive Database received the highest overall score and was the most complete and useful reference source. All of the references, however, lacked sufficient information on management of herbal medicine overdose, and several had incorrect overdose management guidelines that could negatively impact patient care.


CONCLUSIONS
Current herbal reference texts do not contain sufficient information for the assessment and management of adverse health effects of botanical therapies.
Haller
Christine A
CA
Department of Medicine and Clinical Pharmacy, University of California, San Francisco, California, USA. dchaller@worldnet.att.net
Anderson
Ilene B
IB
Kim
Susan Y
SY
Blanc
Paul D
PD
D004341:Drug Evaluation; D006801:Humans; D028321:Plant Preparations / Q000008:administration & dosage / Q000009:adverse effects*; D011039:Poison Control Centers / Q000706:statistics & numerical data*; D012014:Reference Books, Medical
D028321:Plant Preparations