Taking methimazole may cause neuritis, which is a side effect of methimazole. Methimazole belongs to the group of antithyroid drugs. It is indicated for all types of hyperthyroidism. Methimazole can cause clinical manifestations secondary to neuritis. The most common side effect of methimazole is granulocyte inhibition, and some patients may develop symptoms of neuritis, which is manifested by abnormal sensation, sensory hypersensitivity, convulsions, and swelling in the lesioned nerve groups. Patients who take methimazole and develop neuritis should stop taking the drug in time, patients can take vitamin B1, methylcobalamin and other drugs to nourish the nerves and relieve the symptoms of neuritis. Methimazole should be used strictly under the guidance of a doctor, and when side effects occur, a doctor should be consulted for targeted disposition.