Adelaide: The misperception that herbal medicines are 'safe' because they are derived from natural materials and have been in use for thousands of years could see people unknowingly putting their health at risk, say University of Adelaide researchers. In a paper published today in the Medical Journal of Australia, researchers have highlighted a range of issues relating to the preparation of complementary medicines (including herbal products) and their use. The researchers found that some traditional herbal preparations contain toxic chemicals from both animals and plants, as well as heavy metals and pesticides.
"Toxic side effects of
herbal medicines used in traditional societies have typically not been
reported, and this is often cited in favour of their safety. However,
the lack of systematic observation has meant that even serious adverse
reactions, such as the kidney failure and liver damage caused by some
plant species, have gone unrecognised until recently," says lead author Professor Roger Byard, Professor of Pathology at the University of Adelaide.
review – by researchers from the University of Adelaide, Murdoch
University and Curtin University – has important implications for
consumers, as more than half of those using complementary medicines
(including herbal products) do not inform their doctors of use. Patients
often use these products alongside conventional medications and with
other herbal medications.
"Most of the time patients don’t
recognise herbal products as a medicine, so it doesn’t come to mind when
asked what medicines they are taking," says co-author Dr Ian Musgrave from the University's Discipline of Pharmacology.
can also be a situation of 'don’t ask, don’t tell' – medical doctors
may not think to ask patients what herbal medicines they might be
taking, so people don't think to mention it. The problem with this is
that drug interactions are poorly recognised in herbs – not only can
herbal medicines interact with traditional pharmaceutical medicines but
also with other herbal medicines the patient may be using."
authors say that due to relatively light regulation of the industry, the
content and quality of herbal preparations are not as tightly
controlled as standard pharmaceuticals.
"A significant number of
traditional herbal medicines do not comply with Australian regulations.
In some cases ingredients are either not listed or their concentrations
are recorded inaccurately on websites or labels. In other cases a
botanical species may be replaced with another if it is difficult to
source or too expensive. The replacement species may be potentially
toxic. Most worryingly, a few products are illegally adulterated with
standard pharmaceuticals to increase the effectiveness of the herbal
product," Dr Musgrave says.
Professor Byard says: "We feel it
would be appropriate for the Therapeutic Goods Administration to require
manufacturers to have samples independently tested before placing them
on the market. Legal action should be considered in cases of
non-compliance with applicable regulations, and preparations containing
illegal substances should be banned."
Dr Musgrave says: "Any
sensible way to overcome these issues will involve more effort: more
testing, more documentation, and this will naturally incur more costs
for industry. There will be a reluctance from industry to do this, but
while they claim that for thousands of years they have been using herbal
products without such tests, the potential risks to human health mean
that there is due cause for reasonable, scientifically rigorous