A popular sleeping pill could help repair brains damaged by strokes.
In experiments on mice, animals given zolpidem recovered much more rapidly than usual.
If the dramatic results are replicated in people, it could mean that many more stroke survivors regain the ability to eat, dress or walk unaided, greatly improving life for them and their carers.
There are 15 million people worldwide who suffer a stroke each year, with nearly six million deaths.
Stroke is Britain’s third-biggest killer and America's fifth leading cause of death, as well as the main cause of severe disability.
Those who survive are often left living with problems from muscle weakness and paralysis to loss of co-ordination and balance caused by an interruption in the blood supply to the brain.
Hospitals have just one drug that limits damage, but it has to be given within a few hours of falling ill and many patients miss out on it.
After that, physiotherapy is the only option.
The sleeping pill research, from Stanford University in California, raises the possibility that many more patients could be treated.
The hope centres on zolpidem, which has the brand name Stilnoct or Ambien, and is used to treat insomnia.
The researchers found that when mice that had strokes were given the drug, they recovered much faster than untreated animals.
Importantly, the drug was effective when given days after the strokes had taken place.
One test involved placing pieces of sticky tape on their paws and watching how long it took them to become aware of it.
A healthy animal would quickly notice the tape and take it off.
It took the untreated animals a month to recover sufficiently to feel the tape and remove it.
In contrast, those who were started on zolpidem three days after their stroke, spotted the irritant just a few days later.
The mice on zolpidem also regained their balance and dexterity more quickly, the journal Brain reports.
It is thought the drug strengthened signals key to the brain’s repair.
It is hoped that further research in other animals will show that the drug doesn’t just speed up recovery – it also enhances it.
The doses used in the study were too low to make the animals sleepy, so stroke patients shouldn’t feel drowsy when taking it.
However, more research is needed before it can be trialled on people post-stroke and the Stroke Association has urged caution.
Dr Shamim Quadir, the charity’s research communications manager, said: ‘This study suggests that a type of sleeping pill, zolpidem, may aid stroke recovery.
‘However, this is really early stage research that was done on mice.
‘It’s far too early to know what the effect might be on humans, and much more work would need to be done to justify a clinical trial which would help us understand what the impact could be on future stroke treatment.’