Methylcobalamin effects include treating peripheral neuropathy, promoting nerve recovery, and relieving disease symptoms. Side effects include allergic reactions, gastrointestinal reactions and so on. Methylcobalamin is a drug for the treatment of peripheral neuropathy, and the commonly used dosage forms are capsules, tablets, dispersible tablets, and injections. The effects of methylcobalamin are as follows: 1. Treatment of peripheral neuropathy: used in the treatment of many kinds of peripheral neuropathy and megaloblastic anemia caused by vitamin B12 deficiency. 2. Promote nerve recovery: it is used to promote nerve anastomosis in reimplantation surgery and promote the recovery of nerve function. 3. Relieve disease symptoms: used to relieve lumbar disc herniation, sciatica and other neurological symptoms caused by sciatica, to help disease recovery. The side effects of methylcobalamin are as follows: 1. Allergic reaction: manifested as skin rash, itching and other adverse reactions, when found, stop using the drug in time. 2. Gastrointestinal reactions: loss of appetite, nausea, vomiting, diarrhea and other adverse reactions. In addition, the site of intramuscular injection may appear pain or hard nodules, etc. It is recommended to use it strictly under the guidance of a doctor, carefully read the instructions to exclude contraindications, and avoid self-medication.