21 June 2013 Last updated at 07:00 ET By Caroline Parkinson Health editor, BBC News website
Patients given a clot-busting drug within six hours of a stroke are more likely to have a good quality of life 18 months afterwards, an international study suggests.
However, the review of more than 3,000 patients found the drug - alteplase - offered no improvement in survival rates.
The drug is increasingly being used in specialist stroke units in the UK.
The Stroke Association said the Lancet Neurology research was "encouraging".
The treatment is given to patients who have had an ischaemic stroke, when the brain's blood supply is interrupted by a clot.
The sooner patients receive treatment the more likely they are to make a better recovery
A stroke can cause permanent damage such as paralysis and speech problems, and can be fatal.
Without treatment, a third of people who suffer a stroke die, with another third left permanently dependent and disabled.
This international trial, led by researchers at the University of Edinburgh, followed patients from 12 different countries - half had the alteplase treatment, which is given intravenously, and half did not.