Platelets can be caused by a variety of diseases, the common ones are: a. Aplastic anemia, especially acute aplastic anemia, which is a hematopoietic failure disease, due to T lymphocytes attacked the body’s hematopoietic stem cells, resulting in impaired hematopoietic stem cell function, peripheral blood triplet reduction, there will be a low platelet condition. Second, acute leukemia, which is a malignant clonal disease of bone marrow hematopoietic stem cells, can also occur as a result of a particularly low platelet condition due to the massive proliferation of leukemia cells in the bone marrow, resulting in the inhibition of normal hematopoietic function. Third, immune thrombocytopenic purpura, which is an autoimmune disease, due to the production of autoantibodies against platelets, excessive destruction of platelets in the peripheral blood, resulting in a situation where the number of platelets in the peripheral blood is particularly low. Fourth, myelodysplastic syndrome, a disease characterized by pathological hematopoiesis and a high risk of transformation to leukemia, also exhibits a condition in which the platelets in the peripheral blood are particularly low.