At least six Australians needed organ transplants in the past five years after taking herbal supplements.

Key points: Organ donation data shows six organ transplants have been linked to supplement use

Organ donation data shows six organ transplants have been linked to supplement use The figures relate to cases where doctors were able to identify the probable cause of the illnesses

The figures relate to cases where doctors were able to identify the probable cause of the illnesses The data does not indicate what kind of herbal supplement caused the organ failure

Data obtained from national organ donation registries shows, since 2011, three liver transplants and three kidney transplants have been given to people who got sick after taking some kind of herbal supplement.

It comes after West Australian man Matthew Whitby spoke to the ABC after losing his liver — most likely as a result of taking a protein powder with green tea extract and a supplement containing garcinia cambogia.

Registry representatives have told the ABC the figures only relate to cases where doctors were able to identify, and actually documented, the probable cause of the illnesses that led to the transplant.

The data does not indicate what kind of herbal supplement caused the organ failure or whether it was a definitive cause.

Liver transplant specialist Dr Nick Shackel from Sydney's Royal Prince Alfred Hospital said he had dealt with multiple cases of liver failure and transplants associated with herbal supplements.

In many cases, the patients had consumed green tea extract.

"There are compounds in green tea which if taken in excess give you predictable liver failure," he said.

"We simply represent a tip on an iceberg of disease."

His comments counter those of some pharmacologists, who suggest people can only get sick from green tea extract if they have an unpredictable "idiosyncratic" reaction.

There is research that suggests green tea extract can become toxic at median level at the equivalent of 24 cups in a day.

Dr Shackel, who is also a representative of Transplant Australia, said there were only a limited number of organs available to transplant.

"Clearly, this is an avoidable liver injury," he said.

"Given we always have deaths on the waiting list and we have patients who can't be transplanted simply because we don't have enough organs, we'd clearly like these organs to go to people where there's unavoidable causes of liver failure."

Figures suggest there are currently about 1,200 people waiting for a liver or kidney transplant in Australia.

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Supplement regulations up to Government: industry

Steve Scarff from the Australian Self Medication Industry said it was up to the Federal Government to determine whether warnings or more regulations were needed.

"Australia already has one of the most rigorous regulatory systems in the world for complementary medicines," Mr Scarff said.

"There are strict controls over the ingredients that can be used, the manufacturing sites that can be used, the labelling content as well as an obligation to report adverse events."

The Therapeutic Goods Administration said it was investigating reports of liver failure as a part of a wider review.

Following inquiries from the ABC, a spokeswoman said it would liaise with organ donation registries to "obtain more information" and decide on any regulatory action.

"This action could potentially include reducing the allowable limits of particular herbal extracts in complementary medicines," she said.

She said there were 11,000 complementary medicines listed on the Australian Register of Therapeutic Goods "and that there are significant sales of these products".

How many transplants were done in Australia in 2015?

Kidneys made up the majority of the organ transplants in 2015.

Another victim in Western Australia

When his optometrist told him he had macular degeneration, West Australian man Roger wanted to do all he could to retain his vision.

"He recommended that I take a herbal supplement to minimise the risk of it spreading and getting worse," he said.

When the Australian product he had been taking was no longer available, Roger found a similar multi-vitamin on an overseas website.

"I'm an industrial chemist so I investigated those ingredients to make sure there wasn't anything I was unhappy to take," he said.

"I thought at worst they would do nothing."

Within months, Roger was in hospital and being told devastating news.

"I was told that I'd lost 90 per cent of my liver function and that while there was a remote chance it could regenerate, they started preparing me for a liver transplant."

Roger had the transplant in October last year.

He is still recovering and has asked not to be further identified.

His doctors found the most likely culprit for his illness was the multi-vitamin which contained bark extract and green tea extract.

"I feel rather stupid because I had no idea that such a thing could happen," he said.

"I think there should be warnings."