The widespread use of aspirin to prevent strokes is not supported by any scientific evidence and should be stopped in favour of more effective alternatives.
Researchers from the Thrombosis Research Institute in London say that many of the studies which have helped make the treatment so commonplace are flawed.
In a review of 16 studies, only one fulfilled the criteria for a properly designed trial. One paper included emergency cases which should never have been part of any study; another refers to "the same trial" which in fact were two separate studies.
Others, including the New England Journal of Medicine itself, are accused of bad mathematics, and of confusing percentages with actual cases.
Another study claimed that the treatment was most beneficial to those at greatest risk when the reverse was, in fact, the case. The same study also said that the treatment could be safely continued after the patient was discharged from hospital, when there was no evidence to support the statement.
All the studies ignored other treatments which are more effective.