Researchers in Europe are preparing to start the first major trials of stem cell therapy in people with multiple sclerosis.
They want to discover whether injections of the cells can slow, or even reverse, the damage caused by the condition to the brain and spinal cord.
The trial, involving up to 150 patients across Europe, is due to start later this year. It is part-funded by the MS Society in Britain.
The BBC's science correspondent says researchers will collect stem cells from the bone marrow of patients, grow them in the laboratory and then re-inject them into their blood.
The stem cells will make their way to the brain where it is hoped that they will repair the damage caused by MS.
''There is very strong pre-clinical evidence that stem cells might be an effective treatment,'' said Dr Paolo Muraro of Imperial College London.
The BBC reports no proven stem cell therapy is available for MS anywhere in the world.
The MS Society hopes the new trials will eventually lead to a proven treatment - and a reduction in the draw of overseas treatments.