Platelets are the blood cells responsible for stopping bleeding in the body. Platelets have a series of functions such as adhesion, aggregation, contraction and secretion. At the same time, the number of platelets must be maintained within the normal range in order to perform the coagulation function normally. Therefore, the common reasons for poor platelet clotting function are: i. Decreased platelet count, such as immune thrombocytopenic purpura patients, leukemia patients, aplastic anemia and myelodysplastic syndrome. As the number of platelets decreases, poor platelet coagulation occurs. Secondly, it is common that the platelet adhesion function decreases. After the vascular adhesion function decreases, platelets cannot adhere to the endothelium of blood vessels, resulting in reduced coagulation function, and common diseases include vascular hemophilia, platelet anemia, liver cirrhosis, and myelodysplastic syndrome. Also taking anti-platelet drugs, such as aspirin, Bolivar, etc., can also result in reduced platelet coagulation.