Acetylsalicylic acid is better known as Aspirin. Aspirin is not only a medicinal product against pain, inflammation and fever; in low doses, it prevents blood clotting and with it occlusion of blood vessels. If a blood clot blocks a vessel that provides nourishment to the heart muscle, a heart attack develops; if the clot occludes a brain-nourishing vessel, however, a stroke follows. Research has shown that the likelihood of a repeat stroke or heart attack can be reduced by 25% when taking Aspirin.
Unfortunately, however, Aspirin does not act to prevent the appearance of blood clots in all people. Various research studies have indicated that as many as 8%-45% of the people are resistant to the effects of the acetylsalicylic acid. There are numerous reasons for this resistance, one of which may be hidden in your genes.
More information about genetic testing for medications.