Long-term use of Methimazole tablets may cause leukopenia, impaired liver function and other harmful effects. Methimazole belongs to the antithyroid drugs, which can inhibit the synthesis of thyroxine. Methimazole tablets are mainly used for various types of hyperthyroidism. However, long-term use of methimazole tablets can also be harmful, may appear leukopenia; granulocytopenia; less common severe granulocyte deficiency (can be manifested as stomatitis, pharyngitis, fever, etc.), thrombocytopenia, thrombocytopenia and other adverse reactions. Methimazole tablets are also prone to affect the liver function of patients with hyperthyroidism, and if the drug is taken for a long period of time, it may also cause liver function impairment, leading to hypothyroidism and other symptoms. People who are allergic to the ingredients of methimazole tablets, people with severe bone marrow suppression, nursing mothers and other groups are prohibited from taking the drug. If patients need to take methimazole tablets, it is recommended to use the medication under the guidance of a doctor, do not use the medication privately, so as not to aggravate the condition.