The myth that herbal medicines do not have adverse health impacts is having its own dire side-effects, according to a new study.
The review, conducted by pharmacology researchers at the University of Adelaide, Murdoch University and Curtin University, points to a regulatory system that it says does not ensure the safety of products, and leaves consumers and health professionals in the dark about some of the potential effects of herbal remedies.
It found that some traditional herbal preparations contain toxic chemicals, heavy metals and pesticides.
The paper, published in Medical Journal of Australia on Monday, also found that many commonly used herbal medicines such as St John’s wort, ginseng and evening can have adverse pharmacological interactions with prescription drugs and interfere with the outcome of surgical procedures.
According to the paper, fewer than 50 per cent of patients in Australia discuss the herbal remedies they use with health professionals, and these medicines are rarely recorded on hospital admission forms.
People using traditional Chinese medicines should be wary that pharmaceutical agents may actually be added to the preparation. According to the paper, pharmaceuticals such as antibiotics, antihistamines and aspirin are still added to traditional Chinese medicines that can be purchased in Australia.
These substances are presumably added to increase the apparent efficacy of the herbal product, reinforcing its authority as a therapeutic alternative, the paper says.
In addition to the potential risk of ingesting uncontrolled amounts of these drugs, there are risks of allergies to undisclosed ingredients.
There have been reports of Cushing syndrome associated with exposure to undisclosed steroids, aplastic anaemia with exposure to phenylbutazone and hypoglycaemia with ingestion of glyburide.
The lead researcher, Dr Ian Musgrave, called for significant changes to the assessment of herbal, alternative and traditional medicine products, a regulatory system which the paper says, relies on the honesty of the manufacturer.
In some cases ingredients are either not listed or their concentrations are recorded inaccurately on websites or labels. In other cases botanical ingredients may be replaced with another if it is difficult to source or too expensive.
Any sensible way to overcome these issues wll involve more effort: more testing, more documentation, and this will naturally incur more costs for the industry, he said.