Thousands of Australian women, and millions worldwide, take over-the-counter remedies with black cohosh for the relief of menopausal symptoms like hot flushes, night sweats and irritability.
The extract, first used for gynaecological conditions by North American Indians, is a key ingredient in more than 200 drugs and is marketed as a natural and safe alternative to controversial hormone replacement therapy (HRT).
But while studies show the extract is well tolerated, there are emerging reports of a rare but severe side effect on the liver.
Seven women have suffered liver failure in the past decade, five requiring liver transplantation, and in a new case, reported in the Medical Journal of Australia on Sunday, an otherwise healthy 51-year-old Adelaide women also had to undergo a transplant.
Her treating physician, Dr Elizabeth Chow from Flinders Medical Centre in Adelaide, said the patient had taken the drug within the recommended dose over three years.
Dr Chow said the latest case was further proof tighter regulations were required to monitor the use and safety of these preparations.
She called for more randomised-controlled trials to test products and said new guidelines were needed recommending women who take black cohosh to have their liver tested.
"We recommend that liver function be checked before and during use of black cohosh," she said.
The public also needed to be better briefed about the risks of using complementary medicines, and in particular black cohosh, a member of the buttercup family.
"There is a widespread belief in the community that 'natural' plant substances are safe, effective and free of side effects," she said.
The Therapeutic Goods Administration updated labels on black cohosh products in 2006 and again in November 2007 in response to adverse drug events reported worldwide.
Source: AAP NewsWire