Low white blood cells in patients with hyperthyroidism are generally not life-threatening if they are mild; they may be life-threatening if they are too low and cause the onset of infection. Hyperthyroidism low white blood cells is due to increased destruction of white blood cell production reduction or taking anti-thyroid drugs lead to white blood cell reduction. Generally, a mild decrease in white blood cells will not cause harm to human health, and when anti-thyroid drugs, such as propylthiouracil, are discontinued, white blood cells will gradually return to normal. If the white blood cell decrease is obvious, the obvious lack of granulocytes will cause harm to human health, for example, it may cause infectious diseases, wounds do not heal and so on. At this time the medication or treatment should be adjusted according to the patient’s condition. When the hyperthyroidism white blood cells are low, it is recommended that the patient adjust the treatment under the guidance of the doctor, and do not stop the medicine privately.