Low platelet count means that the number of platelets in the peripheral blood is lower than the normal range. The common causes of reduced platelet count include: a. Reduced platelet production, which is common in clinical conditions such as aplastic anemia, acute leukemia, myelodysplastic syndrome, megaloblastic anemia, severe iron deficiency anemia, and paroxysmal sleep hemoglobinuria. The most common disease is immune thrombocytopenic purpura, due to the body produces antibodies against its own platelets, resulting in excessive destruction of platelets, and lead to bone marrow megakaryocyte proliferation disorders, and ultimately caused by the reduction of platelet count, three, external factors caused by the reduction in the number of platelets, including drugs, infections, such as colds, aspirin, heparin, some Antibacterial drugs can cause a decrease in platelet count.