Warning over herbal weight-loss tablets as more cases of liver failure emerge.

The evidence that herbal weight loss pills can be extremely dangerous is mounting.

According to data from the national organ donation registries at least six Australians have required organ transplants in the past five years as a result of taking herbal weight loss supplements, the ABC reports.

The problem has come to the attention of the Australian Therapeutic Goods Administration, which is currently investigating the reports of liver failure as a part of a wider review.

But liver failure is just one possible, and extreme, potential problem. There are others.

One Melbourne woman living in Los Angeles told Mamamia the supplements made her seriously ill.

Actress Georgia Van Cuylenburg, 28, contacted Mamamia after reading about Western Australian man Matthew Whitby who almost died, requiring an emergency liver transplant after ingesting supplements containing green tea extract.

While Van Cuylenburg’s reaction was fortunately not life-threatening, she says she suffered for a year and a half from a range of debilitating symptoms including dizziness, vertigo, stomach upset, lethargy and extreme fatigue after taking herbal pills to help her lose weight before a photo shoot.

Seeking advice from a gastroenterologist, Van Cuylenburg was referred to a liver specialist who found she had dangerously high levels of liver enzymes and ordered her to stop taking the pills.

“My doctor told me he sees at least one patient a month with the same issue and most involve supplement from online or over the counter and very often green tea extract,” she said.

“I have since met a number of people who had family members with the same issue and one colleague who had a similar issue from supplements that gave her a chronic illness.”

Van Cuylenburg suffers from the auto-immune disease alopecia areata,which causes hair loss, and advocates on behalf of other sufferers of the auto-immune disease.

She was led to the green tea-based supplements by a personal trainer because she wanted a quick way to slim down before a photo shoot promoting “strength, muscles and baldness”.

Liver transplant specialist Dr Nick Shackel from Sydney’s Royal Prince Alfred Hospital has dealt with multiple cases of liver failure related to supplements containing green tea extract.

“There are compounds in green tea which if taken in excess give you predictable liver failure,” he told the ABC.

“We simply represent a tip on an iceberg of disease.”

Nigella Lawson talks to Mia Freedman about savouring your food and looking after yourself.

Van Cuylenburg has sworn off supplements and made a full recovery, but worries about the lack of regulation surrounding the sale of such products.

“I think the most important thing for people to gain from this recent surge in stories about supplements is to be educated and to make smart, informed decisions,” she said.

“These companies don’t have to back up claims or prove anything and we trust them.

“I never ever would have dreamed this would happen to me and I would hate for anyone else to go through this because they didn’t take the time to question the facts or ask a professional.”

A spokeswoman for the TGA said they would liase with organ donation registries to “obtain more information” and decide on any regulatory action, such as potentially reducing the allowable limits particular herbal extracts like green tea, the ABC reports.

She said there are currently 11,000 complementary medicines listed on their register that sales of such products were “significant”.