But, according to a study, the risk could be cut by a third if patients take the combined drugs, the Daily Express reported.
About 150,000 people have a stroke caused by a blood clot or bleeding in the brain in Britain every year - one every five minutes. It is the leading cause of severe adult disability.
The risk of recurrence was cut dramatically for victims of a mini-stroke - transient ischemic attack (TIA) - by adding the drug Plavix to aspirin, according to the study findings presented to an international conference of the American Stroke Association in Honolulu.
Dr Claiborne Johnston of the University of California, said that a mini-stroke would not usually cause permanent harm but early treatment was critical to prevent a major stroke.
Mini-stroke victims are almost 10 times more likely to have one.
Dr Johnston said: "If we start dual treatment early, it looks like we can reduce the risk of another stroke by more than 30 per cent."
Aspirin alone cut the risk by about 20 percent, he added.