Methylcobalamin and Vitamin B₁ taken together have the ability to nourish the nerves and maintain normal nervous system function. Methylcobalamin belongs to a kind of endogenous coenzyme B₁₂, this drug can inhibit neurodegeneration, restore the reduced neurotransmitters and neuraxial transmission, improve nerve excitability, and promote the formation of myelin sheaths of neurons; Vitamin B₁₁₁ can participate in the formation of coenzymes, and it can maintain the function of the nervous and digestive systems. Taken together, the two drugs can exert the effect of nourishing the nerves and maintaining normal nervous system function. Taken together, methylcobalamin and vitamin B₁ can not only treat neuritis, dyspepsia, and pediculosis triggered by vitamin B₁ deficiency, but also have efficacy in peripheral neuropathies and megaloblastic anemia (caused by vitamin B₁₂ deficiency). Methylcobalamin is contraindicated in people who are allergic to the drug because of occasional side effects such as allergy (requiring discontinuation of the drug), loss of appetite, nausea and vomiting. Vitamin B₁ is virtually non-toxic, but only in overdose may cause irritability, fatigue, headache and other discomforts, and should not be used in combination with foods and medications containing tanning substances. Mecobalamin and Vitamin B₁ are prescription medications, and their use together must be under the direction of a healthcare professional.