The differences between methylcobalamin and vitamin B12 are different ingredients, different indications, and different adverse effects, among others. 1. Different ingredients: the main ingredient of methylcobalamin tablets is methylcobalamin, and the main ingredient of vitamin B12 is vitamin B12. 2. Different indications: methylcobalamin tablets are mainly used in the treatment of peripheral neuropathy, vitamin B12 is suitable for the treatment of macrocytic anemia. 3. Adverse reactions are different: some patients may have adverse reactions such as loss of appetite, vomiting, diarrhea, nausea and rash when taking methylcobalamin tablets, and vitamin B12 has adverse reactions such as hypokalemia as well as hyperuricemia in the process of taking. In addition the dosage, precautions and so on will be different, it is recommended that patients under the guidance of a doctor, strictly follow the doctor’s instructions to use the drug, not blindly use the drug or change the dose of the drug without authorization, so as not to cause adverse effects on the body.