Methylcobalamin can be taken for hyperthyroidism. Methylcobalamin is coenzyme vitamin B12, mainly used for the treatment of peripheral neuropathy and megaloblastic anemia caused by vitamin B12 deficiency. Hyperthyroidism can be taken after meeting the indications and excluding contraindications, but need to be taken under the guidance of a physician. Adverse reactions occurring with the use of methylcobalamin are commonly gastrointestinal loss of appetite, nausea, vomiting, diarrhea, and rarely allergy, and is contraindicated in patients with a history of allergy to methylcobalamin. If eating methylcobalamin appeared abnormal, or accompanied by other symptoms, should go to the hospital in time to see a doctor, clear reasons to give targeted treatment. The drug needs to be applied under the guidance of a doctor, not self-medication.