Some traditional Chinese medicines are laced with pharmaceuticals, heavy metals and even endangered animals, new research has revealed.

Traditional Chinese medicines (TCMs) have long been thought by some as a more natural, herbal approach to curing ailments.

But now a study carried out by Curtin University, Murdoch University and the University of Adelaide has found 90 per cent of 26 widely available medicines tested were not fit for human consumption.

Key points: Study found 90pc of 26 widely available medicines not fit for human consumption

Study found 90pc of 26 widely available medicines not fit for human consumption Half contained illegal substances, including toxic metals, prescription medication, stimulants

Half contained illegal substances, including toxic metals, prescription medication, stimulants Some contained arsenic, lead, Viagra, rat poison and DNA of endangered species

Some contained arsenic, lead, Viagra, rat poison and DNA of endangered species Researcher says 'honour system' of TGA listing being exploited

Half contained illegal substances, including toxic metals, prescription medications, stimulants and animal DNA, none of which were listed on the product's label.

TCMs are a multi-billion-dollar industry and it is estimated 50 per cent of Australians have used alternative therapies at some point.

Researchers employed a new method involving highly sensitive DNA sequencing, toxicology and heavy metal testing to assess the composition of the TCMs.

The study does not disclose the brands of medicines checked, but confirmed they were purchased in Adelaide and available for sale in retailers and markets nationally.

Curtin University lead researcher Professor Michael Bunce said the results were shocking.

"Half of them have illegal ingredients in them, we've determined from DNA, half of them have got pharmaceuticals added to them that are clearly synthetic in nature and have not come from natural compounds," he said.

"Another proportion of them have heavy metals beyond the safe ingestion recommendations ... 90 per cent of them are really not fit for human consumption."

Murdoch University biochemist Dr Garth Maker said contamination by undisclosed pharmaceuticals was a health concern.

He said over-the-counter drugs like paracetamol and ibuprofen were found but also steroids, blood thinner warfarin and even sildenafil, the active ingredient in Viagra.

"We were surprised but at the same time, there definitely seems to be an element of deception in designing these things to have a specific outcome," he said.

"They may contain ephedrine, which will give a lot of people a buzz, and therefore they feel good and they think 'this is fantastic medicine, I should keep taking it'."

Arsenic, lead, strychnine found in some medicines

Arsenic, cadmium and lead were found in some of the Chinese medicine.

One of the herbal concoctions contained over 10 times the recommended daily limit for arsenic exposure.

Another contained strychnine, which is used as a rat poison and at lower levels as a performance-enhancing drug.

"Obviously if someone has been taking this for a very long time, they may have unwittingly exposed themselves to reasonably high levels of the poison strychnine," Dr Maker said.

"If we don't know what's in them, it's very difficult to predict the interactions, and also [they can be] taken with other medications.

"That's obviously of great concern if they [have] been given to children, or pregnant women, the potential outcomes there are very serious," he said.

DNA of endangered species detected

Professor Bunce said one of most alarming results was the DNA presence of endangered species.

The project's lead researcher Professor Michael Bunce of Curtin University. ( ABC News: Laura Gartry )

"One herbal medicine that's for sale had trace amounts of snow leopard DNA in it," Professor Bunce said.

"We also found DNA from pit vipers, frogs and trace amounts of cat and dog DNA."

Whether the animal products were primary ingredients or the result of poor manufacturing processes is yet to be determined.

Curtin University researcher Dr Megan Coghlan said the result demonstrated that despite heavy penalties for illegal trafficking of protected wildlife, poaching and smuggling was still occurring, with traditional medicine a significant "push-factor".

"Moreover, consumers of this particular medicine would be unaware that they have been ingesting content from this species, as it was not listed as an ingredient," Dr Coghlan said.

Push for more regulation of herbal imports

Professor Bunce said each herbal medicine sold in Australia needs to be listed with the Therapeutic Goods Administration (TGA), but only 12 of the products tested were registered with the agency and are deemed "low-risk".

The remaining 14 were not registered by the TGA and therefore should not be available to Australian consumers in a commercial quantity.

The TGA relies on the importer to make a true declaration about the ingredients, an honesty system Dr Garth believes is being exploited.

"We would hope there would be a rigorous screening procedure adopted by the TGA to actually monitor these compounds, medicines before they are actually put on sale," said Dr Garth.

The TGA declined to be interviewed but a spokeswoman said in a statement that most complementary medicines are listed medicines and considered to be of relatively low-risk to consumers.

"[They are] complementary because they may only contain pre-approved low-risk ingredients and must not make claims or imply that they have benefit for the treatment or prevention of a serious illness," she said.

"The TGA has worked directly with persons responsible for introducing the product to the Australian market referred to in the article to ensure compliance with the requirements of Australia's therapeutic goods legislation."

At least one of the products found to illegally contain ephedrine has since been placed on a Customs watch list and authorities have been told to stop any future imports.

The ABC can reveal at least five of the tested products already had customs warning alerts overseas, including two in Malaysia and one in the United Kingdom.

Mr Maker said the practise is widespread and increasing.

Contamination 'not widespread': Chinese medicine proponent

National President of the Federation of Chinese Medicine Society of Australia Professor Tzi Chiang Lin said he did not believe such findings would be widespread across the industry.

"Of course, there are some people ... that are not that good and they might be making something not very nicely," he said.

"[But you] can not [put] blame on the whole profession, it will be one or two individuals. It may be one or two cases [that have] happened, but not many," he said.

Professor Lin said the TGA's current regulatory regime is "perfect".

"The low-risk herbal medicines [are] already regulated very closely by [the] TGA, and they supervise very strictly the manufacturers in China," he said.

"Over-regulation will mean trouble for the industry and [would not be] fair for the profession."

Professor Lin said traces of heavy metal contamination were not particularly unusual and probably linked to the soil ingredients were grown in, as they had chemical fertilisers added.

The study's findings have been published in the journal Nature Scientific Reports.

Researchers plan to now scrutinise up to 300 other widely available herbal medicines.