Acetylsalicylic acid (brand name Aska) has an antiplatelet effect by inhibiting the production of thromboxane, which under normal circumstances binds platelet molecules together to create a patch over damaged walls of blood vessels. Because the platelet patch can become too large and also block blood flow, locally and downstream, acetylsalicylic acid is also used long-term, at low doses, to help prevent heart attacks, strokes, and blood clot formation in people at high risk of developing blood clots. Also, low doses of acetylsalicylic acid may be given immediately after a heart attack to reduce the risk of another heart attack or of the death of cardiac tissue. Acetylsalicylic acid may be effective at preventing certain types of cancer, particularly colorectal cancer. Aska is available as gastro resistant tablets that contain 100 mg of acetylsalicylic acid.