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Herbal therapies and safety

People commonly deride alternative therapies as being ineffective, often followed up by an aside that "at least they are safe". Not so. Bandolier has pointed out that there may be harm associated with acupuncture, for instance ( Bandolier 68 ).

Herbal remedies have good evidence for efficacy. That is true of St John's Wort ( Bandolier 31 ), feverfew ( Bandolier 65 ) and gingko ( Bandolier 18 and 48 ) if not ginseng . They are effective because they contain chemicals that interact with receptors or enzymes. Just as aspirin, morphine and cocaine are herbal derivatives with both good and bad effects, we should not be surprised that other herbal remedies may also have associated harm. A warning about the association of Chinese herbal remedies and renal failure was issued recently [1], with a reminder that yellow card reporting is important.

Adverse reactions to herbal medicines are not just due to the herbs themselves. Some preparations might contain other, toxic, herbs, heavy metals, or corticosteroids [1].

A review [2] examines a number of common herbal remedies. It provides no search strategy, though does include references to meta-analyses and systematic reviews, and to high-quality randomised clinical trials for efficacy. It gives information on the regulatory framework for herbal remedies. Most usefully it describes mechanisms of action, cautions, drug interactions and adverse effect information, and is well referenced. It is a worthwhile read for pharmacists and for those interested in herbal remedies.


  1. MCA/CSM. Current Problems in Pharmacovigilance. 1999 25 November.
  2. TB Klepser, ME Klepser. Unsafe and potentially unsafe herbal therapies. American Journal of Health-System Pharmacists 1999 56: 125-38.
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