Platelet decline refers to the number of platelets in the peripheral blood is lower than normal, the number of platelets below normal can be seen in a variety of reasons, the common causes are: a. Infection caused by the number of platelets decline, such as viral infections, such as the flu, rubella virus may cause a mild decline in the number of platelets. Second, drugs caused by platelet decline, such as anti-inflammatory painkillers ibuprofen, as well as certain antibacterial drugs cephalosporins, etc., may cause a mild decline in the number of platelets. Third, platelet decline caused by blood system diseases, the most common ones are autoimmune thrombocytopenic purpura, aplastic anemia, myelodysplastic syndrome, leukemia, etc., all of which can cause a decrease in platelet count. Fourth, after chemotherapy for tumor patients, due to the damage to the hematopoietic stem cells, it will also cause the situation of platelet decline. Therefore, there are various reasons for platelet decline in clinical practice.