There are many reasons for platelet instability, including physiologic factors, pathologic factors, drug-induced and so on. 1. Physiological factors: Platelet counts may vary throughout the day, being lower in the early morning and higher in the afternoon. Platelet count is also associated with seasons, lower in summer and higher in winter. In addition, the physiological period of women also has an effect on platelets, which is lower before the physiological period and higher after the physiological period. Platelet count increases in the middle and late stages of pregnancy and decreases after delivery. 2. Pathological factors: anemia, blood loss, infection, myelodysplastic syndrome and other diseases will lead to platelet elevation, aplastic anemia, leukemia, systemic lupus erythematosus, thrombocytopenic purpura and other diseases will cause platelet reduction. 3. Drug-induced: drugs that can cause platelet elevation or reduction include antibacterial drugs such as Jimmy Farsin, Moxifloxacin, Lomefloxacin, dermatological drugs such as Avitamin A ester, Isotretinoin, leukocytostatics such as Morastine, immunosuppressants such as Tacrolimus, and glucocorticosteroids such as Hydrocortisone, and so on. Platelet instability may also have other causes, such as immune factors, etc. It is recommended to go to the hospital in time, complete the examination to clarify the cause of the disease, and then under the guidance of the physician to give targeted treatment or therapy.