Five severely disabled stroke patients show signs of recovery following the injection of stem cells into their brain.
Prof Keith Muir, of Glasgow University, who is treating them, says he is "surprised" by the mild to moderate improvements in the five patients.
He stresses it is too soon to tell whether the effect is due to the treatment they are receiving.
The results will be presented at the European Stroke Conference in London.
Commenting on the research, Dr Clare Walton of the Stroke Association said: "The use of stem cells is a promising technique which could help to reverse some of the disabling effects of stroke. We are very excited about this trial; however, we are currently at the beginning of a very long road and significant further development is needed before stem cell therapy can be regarded as a possible treatment."
The stem cells were created 10 years ago from one sample of nerve tissue taken from a foetus. The company that produces the stem cells, Reneuron, is able to manufacture as many stem cells as it needs from that original sample.
It is because a foetal tissue sample was involved in the development of the treatment that it has its critics.
Among them is anti-abortion campaigner Lord Alton. "The bottom line is surely that the true donor (the foetus) could not possibly have given consent and that, of course, raises significant ethical considerations," he said.
Reneuron says the trial - which it funded - has ethical approval from the medicine's regulator. It added that one tissue sample was used in development 10 years ago and that foetal material has not been used since.