The formation of blood clots is a natural process that helps the body repair the damaged blood vessels but in some cases like venous thrombosis, blood clots form in the veins as a person becomes immobilized and muscles are not contracting enough to push the blood back to the heart. Similarly in arterial thrombi, blood clots form in the arteries.

In case of persons suffering from atherosclerotic disease, plaque forms along the lining of the arteries and grows there causing several complications like a stroke, heart attack or the peripheral artery disease. Blood clots form in the heart when it does not beat in an organized manner and blood becomes stagnant which causes its clotting. In case of an injury or a cut clotting takes place naturally as it helps stop the flow of blood from the wound.