The full range of side effects of methimazole involves multiple systems throughout the body, with rashes, pruritus, and leukopenia more commonly seen. Less commonly seen are severe granulocyte deficiency, aplastic anemia, and possibly loss of taste, gastrointestinal reactions, arthralgia, dizziness, headache, vasculitis, etc. Rarely hepatitis, interstitial pneumonitis, nephritis. 1. Blood system damage: leukopenia, granulocyte deficiency, aplastic anemia, thrombocytopenia, coagulation factor reduction, acute hematopoietic arrest, acute bone marrow failure and other manifestations. 2. Nervous system damage: loss of taste, dizziness, headache, weakness and drowsiness. 3. Digestive system damage: nausea, vomiting, loss of appetite, diarrhea, liver function abnormality, toxic hepatitis, hepatic coma and other manifestations. 4. Immune system damage: rash, itchy skin, fever, chills, erythema, skin pigmentation, vasculitis, urticaria and other manifestations. 5. Others: hypothyroidism, renal function abnormalities, interstitial pneumonia, etc. Methimazole must be used properly under the guidance of a doctor. Use with caution in pregnant women, patients with abnormal liver function, granulocytopenia, etc. It is contraindicated for those who are allergic to methimazole or any components of this product.