The cause of high platelets may be physiological factors (such as strenuous exercise, etc.) or pathologic factors (such as primary thrombocythemia, reactive thrombocytosis, etc.). The normal value of platelets is (100-300)×10^9/L, and more than 400×10^9/L is considered pathologic. 1. Physiological elevation: common causes such as strenuous exercise, stress reaction, etc., platelet elevation usually does not exceed 400×10^9/L, after removing the causative factors, the platelet count can return to normal. 2. Pathological elevation (1) Primary platelet elevation: it is common in many kinds of myeloproliferative tumors, such as true erythrocytosis, chronic myeloid leukemia, primary thrombocythemia and so on. (2) reactive platelet elevation: mainly due to secondary platelet elevation caused by primary diseases, such as acute and chronic inflammation, acute hemolysis, certain cancers, etc., mostly below 500×10^9/L. Warm tips: patients with elevated platelets should consult a doctor in time to clarify the cause and actively treat if necessary.