Writing in the March edition of Phytomedicine, Shao Kang Hung, Sarah Hillier and Edzard Ernst, found high quality adverse event reports (AER) had risen from zero to 34.2 per cent between 1996 and 2008.
Over the same period the number of low-quality AERs dropped from 13.3 per cent to 2.5 per cent.
“Our results are consistent with the hypothesis that the quality of case reports of adverse effects of HMPs (herbal medicinal products) has improved during the last three decades,” they wrote of the 137 case reports they summarised. “However, due to several caveats, our data should be interpreted with caution.”
They noted there was, “an overall lack of clear information on product names or manufacturers of HMPs.”
“Almost 80 percent of all case reports did not state the product names or the manufacturers of the HMPs,” they wrote, noting a WHO position paper that stated:
“There is around the world a confusing myriad of names of herbal products and of the plants or parts of plants used,” in AERs.
They said spontaneous reporting systems such as the UK Yellow Card Scheme established by the medicines regulator played, “a crucial role in the early and rapid detection of adverse effects, they are far from infallible.”
The researchers acknowledged limitations to their study such as the fact they only scrutinised AERs in English.
Volume 18, Issue 5, 15 March 2011, Pages 335-343
‘Case reports of adverse effects of herbal medicinal products (HMPs): A quality assessment’
Authors: Shao Kang Hung, Sarah Hillier, Edzard Ernst