If the platelet count is mildly elevated and accompanied by infection, fever, bleeding and trauma, it is likely that these factors have caused the platelet reactivity to increase, and no special treatment is needed in this case. However, in patients with underlying diseases such as hypertension, coronary artery disease and cerebral thrombosis, even if the platelet count is mildly elevated, anti-platelet drugs such as aspirin should be given to prevent thrombosis. If the platelet count is significantly elevated, it is common to see primary thrombocytosis, in which case the diagnosis needs to be confirmed by bone marrow aspiration. If the diagnosis of primary thrombocythemia is confirmed, hydroxyurea is required to lower the platelet count, interferon is applied to lower the platelet count, and later lifelong maintenance medication is required.