Methylcobalamin and Vitamin B1 are okay to take together when peripheral nerve injury occurs, but the medication needs to be used under the supervision of a doctor. Methylcobalamin belongs to endogenous coenzyme B12, this drug can participate in the synthesis of brain cells and spinal cord neurons thymine nucleoside, to promote the formation of neuronal myelin sheaths, suitable for peripheral neuropathy. Vitamin B1 has a protective effect on the nervous system in the human body, these two drugs do not conflict with the efficacy of patients with peripheral nerve injury, it is possible to take the two drugs together. Methylcobalamin may cause loss of appetite, nausea and vomiting, diarrhea, skin rash and other side effects during the use of the drug, allergic to this drug is prohibited. If the drug does not work for more than a month, it is not necessary to continue using it. Vitamin B1 has little or no toxicity at recommended doses, but overdose may cause headache, irritability, loss of appetite, diarrhea, swelling, and fatigue. This drug is contraindicated in people who are allergic to it. This drug should not be used with herbs and foods containing tannin, which can be deteriorated when encountering alkaline drugs such as sodium citrate and sodium bicarbonate. If you want to take methylcobalamin and vitamin B1 at the same time, you must be instructed by a medical professional.