B12 should refer to vitamin b12, and methylcobalamin and vitamin b12 are not recommended to be taken together. Methylcobalamin is a derivative of vitamin b12, which has a good improving effect on neuronal conduction. It can promote nucleic acid-protein-lipid metabolism through the methyl conversion reaction, promote nucleic acid and protein synthesis, promote intra-axonal transport and regeneration of axons as well as the formation of myelin sheaths, and prevent axonal degeneration. Methylcobalamin can be used for the treatment of megaloblastic anemia caused by vitamin B12 deficiency, as well as for the treatment of peripheral neuropathy. Vitamin B12 is mainly used for megaloblastic anemia and subacute combined degenerative neuropathy. Taking these two drugs together is a duplication of medication, leading to overdose and adverse drug reactions, such as abdominal pain and bloating. Therefore, it is not recommended to take methylcobalamin and vitamin B12 at the same time, if there is a need for medication, it is recommended that the use of drugs under the guidance of a doctor, do not abuse the drug on their own, so as not to cause adverse reactions.