A woman who grew bone fragments in her eyelid after undergoing cosmetic surgery using stem cells should serve as a warning to Australians considering unproven stem cell treatments, an expert says.

The United States woman underwent more than six hours of surgery to remove the fragments from her eyelid and around the eye, three months after having the cosmetic surgery at a Beverly Hills clinic.

The first operation, described in the December edition of Scientific American, used stem cells extracted from the woman's abdominal fat through liposuction, which were injected into her face.

The $20,000 facelift also incorporated a dermal filler containing calcium, which surgeons believe reacted with the stem cells and turned them into bone.

Cosmetic and regenerative surgery claiming to use stem cells extracted from liposuction is also available in Australia.

While it is not illegal, the only scientifically proven medical treatment using stem cells is bone marrow transplants for diseases including leukaemia, which have been around for about 40 years.

Associate Professor Megan Munsie, from Stem Cells Australia at the University of Melbourne, said the report showed that a cautious approach was needed to developing stem cell therapies.

''There is no doubt that stem cells have an incredible capacity to act as the body's repair kit,'' Professor Munsie said.

''But they need to be given the right instructions, otherwise, as happened to this woman, they can turn into the wrong type of cells.

''I'm concerned that potential patients might think that because the treatment involves using their own stem cells, there is no risk.

''But, as this case graphically illustrates, this is simply not true,'' she said.

''The unproven stem cell cos- metic procedure caused substantial discomfort to the patient and may have cost her sight in the affected eye.

''This, together with the reputed $US20,000 charge [$A19,000], is too high a price.''

Professor Munsie said the case was another example of why any new stem cell treatment must be based on sound evidence and shown to be safe and effective in clinical trials before being widely adopted and sold to patients.

The same stem cells used in the woman, mesenchymal stem cells (MSCs), are used for osteoarthritis patients in Australia.

The science behind this approach is that MSCs found in fat tissue have immunosuppressive and regenerative properties.

However, there are only three registered clinical trials in Australia testing MSCs and osteoarthritis for safety and efficacy, none of them complete.

The cosmetic surgeon who carried out the corrective operation on the woman, Allan Wu, told Scientific American that although the patient was now doing well some stem cells could linger in her face and again turn into bone or other out-of-place tissues. AAP