Platelets (also called thrombocytes) are substances found in blood. They promote coagulation or blood clotting. When a blood vessel is injured, causing bleeding, platelets in the blood begin to accumulate at the injury site, adhering to each other and to the torn vessel lining. This aggregation loosely plugs the injury, preventing further blood loss until the blood can clot, forming a scab and stopping the bleeding. Platelets are often visible as a clear, viscous liquid which forms over a small cut.

Anticoagulant drugs, such as aspirin, often work by inhibiting platelet aggregation and blood clotting. This results in longer bleeding times, but also reduces the chance that a blood clot will form inside an artery, possibly leading to stroke.

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Article : "VASCULAR DEMENTIA"