There are physiologic and pathologic causes of high platelet count. Normal platelet count is (100~300)×10⁹/L, and a platelet count of more than 300×10⁹/L in the blood is called high platelet. 1. Physiological reasons: Normal platelet count varies from 6% to 10% in a day, higher in the afternoon than in the morning, higher in winter than in spring, higher in plateau than in plain, higher after menstruation, higher after strenuous exercise or labor, which is a normal physiological phenomenon, no need to worry. 2. Pathological causes: myeloproliferative diseases, primary thrombocythemia, acute infections, acute hemolysis, acute blood loss, after splenectomy, etc., can lead to increased platelet count. There are many reasons that lead to high platelet count, it is recommended to go to the hospital in time for relevant examinations to clarify the cause of the disease and receive treatment under the guidance of the physician.