It is possible that taking a hyperthyroid medication may cause a decrease in white blood cells. Antithyroid drugs are medications that eliminate or relieve the symptoms of hyperthyroidism. Commonly used antithyroid drugs in clinical practice are thioureas, iodine and iodide, radioactive iodine and beta-blockers. Thioureas are prone to leukopenia and are prone to infections, which can be characterized by fever and sore throat. It should be noted that hyperthyroidism itself can also lead to leukopenia. When there is a lack of granulocytes, you can use Ricodin or granulocyte colony-stimulating factor can promote bone marrow hematopoiesis under the guidance of the doctor. Hyperthyroidism patients with leukopenia should be treated under the supervision of a doctor.