Large platelets, platelets with a diameter of more than 10 micrometers or more. In normal human peripheral blood, a certain proportion of large platelets is maintained. Reduced numbers of large platelets are common in cases of hypoplasia, bone marrow hematopoiesis, and bone marrow hematopoietic failure, the most common disease being aplastic anemia. Aplastic anemia is an autoimmune disease, which is caused by T-lymphocytes attacking hematopoietic stem cells, resulting in progressive hypopoiesis. Therefore, if there is a low number of large platelets, the first thing to do is to see if the bone marrow hematopoietic function is declining, and blood tests should be done to see if the number of white blood cells, the number of red blood cells, and the number of platelets are decreasing. If the number of these three types of cells decreases, it is necessary to do a timely bone marrow aspiration to see if there is a situation of bone marrow hematopoiesis hypoplasia. If there is bone marrow hematopoiesis, basically consider aplastic anemia, and need to be given drugs such as conilone, cyclosporine and other treatments.