Australia requires black cohosh liver warning

Black cohosh is a member of the buttercup family, and it a perennial plant native to North America. It has a long history of use for by women to reduce menopausal symptoms such as hot flushes.

However TGA said on its website​ it is introducing the requirement after reviewing 47 cases of liver reactions worldwide. It said: "Although some reports are confounded by multiple ingredients, by multiple medications, or by other medical conditions, there is sufficient evidence of a causal association between black cohosh and serious hepatitis."​

But it goes on to say: "Considering the widespread use of black cohosh, the incidence of liver reaction appears to be very low."​

While existing black cohosh containing products on the Australian market have 12 months to comply, any new products launched from now on must carry the statement: "Warning: Black cohosh may harm the liver in some individuals. Use under the supervision of a healthcare professional."​

The decision has met with dismay from herbal experts around the world.

Speaking to NutraIngredients.com Professor Edzard Ernst, director of complementary medicine at the Peninsula Medical School, Universities of Exeter & Plymouth, said the TGA's decision is a "gross overreaction"​ to the evidence for toxicity.

He said that in the two or three cases he is aware of where patients taking black cohosh have developed liver problems, the reports have been of very poor quality: there was no in information on what else these patients may have been taking.

"The cause and effect relationship is very difficult to establish on the basis of such a small amount of case reports. One should investigate the matter further."​

He added: "There is no plausible mechanism to understand how black cohosh damages the liver, if it does."​

Professor Ernst believes that once the warning is out there, it will be very difficult to remove since the task now is to disprove the liver toxicity claim. It is sure to be damaging to the reputation of the herb.

While he is not convinced that the evidence to support the benefits of black cohosh is rock solid, he said: "If it is effective it is a shame that people will be deterred from using it."​

Rachel Abela, an Australian naturopath with Holland and Barrett in the UK, said that the impact of the warning on the Australian herbals market depends on the stance that GPs take with patients.

"A lot of loyal customers take herbals on a regular basis. How much this could affect them depends on the individual."​

Abela said that, in the past, there have been issues over contamination of black cohosh with other, potentially hazardous species.

In the US the American Herbal Products Association (AHPA) sought to tackle this last summer with the introduction of a trade recommendation that manufacturers ensure that they are selling genuine black cohosh - the Actaea racemosa​ species, otherwise known as Cimicifuga racemosa​ - and that it is not adulterated with other species such as A. cimicifuga​ (aka Cimicifuga foetida​), Actaea dahurica​ (C. dahurica​) or A. heracleifolia​ (C. heracleifolia​).

AHPA spokesperson Karen Robin told NutraIngredients.com that the organization believes that adulteration is an economic, not a safety, issue.

AHPA noted in a statement that TGA did not reference its sources, explain the methodology behind its review, or give details of how it reached its conclusion.

Steven Dentali, AHPA's vice president for scientific and technical affairs, is regarded as an expert on black cohosh safety. A National Institutes of Health workshop in 2004 which he attended concluded that the evidence for liver toxicity "remains equivocal but certainly warrants continued monitoring"​.

The case for warnings on black cohosh has previously been backed by the campaigning consumer group Center for Science in the Public Interest, which believes there is sufficient evidence to link it to an increased risk of breast cancer metastasis and liver failure.