Primary Thrombocytosis, described by Epstein and Goedel, is a nonreactive, chronic myeloproliferative disorder. Essential thrombocytosis is associated with sustained megakaryocyte proliferation that increases the number of circulating platelets. Traditionally, essential thrombocytosis was considered a clonal disorder that involved pluripotent stem cells; however, studies have indicated that some patients may have polyclonal hematopoiesis. Essential thrombocytosis is characterized by a platelet count greater than 600,000/μL, megakaryocytic hyperplasia, splenomegaly, and a clinical course complicated by thrombotic and/or hemorrhagic episodes. Primary Thrombocytosis can bring people complications. Severe trauma or bleeding after operation may threat to life. Aspirin and other anti-inflammatory drugs can make bleeding worse.