Aspirin is an antiplatelet medicine, which means it reduces the risk of clots forming in your blood. This reduces your risk of having a stroke or heart attack.
Normally, when there is a cut or break in a small blood vessel, a blood clot forms to plug the hole until the blood vessel heals.
Small cells in the blood called platelets make the blood clot. When a platelet detects a damaged area of a blood vessel, it produces a chemical that attracts other platelets and makes them stick together to form a blood clot.
Aspirin reduces the ability of the platelets to stick together and reduces the risk of clots forming.
Please see the link below for more information
Aspirin Advice Leaflet for patients