Diabetes mellitus with peripheral neuropathy, take methylcobalamin can play a role in the treatment of peripheral neuropathy; but not with peripheral neuropathy of diabetic patients to eat methylcobalamin has no obvious benefits, is not recommended to eat. Mecobalamin belongs to the vitamin class of drugs, can promote the metabolism of nucleic acid and the use of folic acid, promote the regeneration of nerve axons and axonal transport function, inhibit neurodegeneration, can be used for the treatment of megaloblastic anemia and peripheral neuropathy due to vitamin B12 deficiency. Therefore, for patients suffering from diabetic peripheral neuropathy taking methylcobalamin can treat peripheral neuropathy, but diabetic patients without peripheral neuropathy have no particular benefit from taking methylcobalamin. Adverse reactions such as nausea, vomiting, diarrhea, and loss of appetite may occur after use of the drug. Persons involved in working with mercury and its compounds should not take large quantities of this drug for long periods of time. It is contraindicated for those who are allergic to methylcobalamin or any of the excipients in this drug. Patients who need to take methylcobalamin for treatment should use the drug under the supervision of a doctor.