If a patient consults an herbalist in the UK or anywhere else he/she will, in all likelihood, not be treated according to the principles of ‘rational herbal medicine’, i.e. with one evidence-based herbal medicine that has been demonstrated to be efficacious for her condition. Instead, treatment will be individualised and concocted according to diagnostic criteria unknown or obsolete in conventional medicine. Thus 10 patients with the identical mainstream diagnosis might receive 10 different mixtures of herbs, none of which is evidence-based. This is true for traditional herbalisms of all kinds, e.g. Chinese, Indian or European.
Some claim that this type of individualised approach cannot be tested in clinical trials, but this notion can easily be shown to be wrong: several, albeit not many such studies testing individualised herbalism have been published. To the dismay of traditional herbalists, their results fail to confirm that such treatments are effective for any condition.
Now a further trial has become available that importantly contributes to this small and precious knowledge-base. Its authors, all enthusiasts of individualised herbalism, randomised 102 patients suffering from hip or knee-osteoarthritis (OA) into two groups. The experimental group received tailor-made mixtures of 7 to 10 Chinese herbs which were assumed to be helpful. The control group meanwhile took a mixture of plants known to be ineffective but tasting similar. After 20 weeks of treatment, there were no differences between the groups in any of the outcome measures: pain, stiffness and function.
These results thus confirm the findings of previous, similar trials of individualised herbalism suggesting that this approach is not demonstrably effective. As this type of therapy employs a multitude of ingredients, the danger of adverse-effects and herb-drug interactions might be considerable. It seems to follow, that the risks of individualised herbalism do not outweigh its benefits.
For GPs, this matters in several ways.
Doctors have the duty to provide evidence-based advice and therefore they have little choice but to inform their patients that individualised herbalism is not a reasonable therapeutic option.
Patients and clinicians alike often have a positive impression of herbal medicine which is based on the fact that certain herbal medicines – for instance, St John’s Wort – are, in fact, evidence-based.
Yet, I fear, that neither the public nor the regulators, who are about to regulate this sector in the UK, are aware how poor the evidence for the most commonly used type of herbalism truly is.
Professor Edzard Ernst is the emeritus professor of complementary medicine at the Peninsula Medical School, University of Exeter