Among the adverse reactions of methylcobalamin, those involving the gastrointestinal tract are very mild, that is, only 5% or 1‰ of people will experience loss of appetite, nausea, vomiting or diarrhea, and these symptoms cannot be considered as hurting the stomach, it has no obvious stimulation to the gastrointestinal tract, and it can even lead to damage to the gastric mucosa, gastric ulcers and gastric bleeding. Methylcobalamin is a drug similar to vitamin B12, which is mainly involved in important physiological functions in the body, that is, the circulation of one carbon unit, so it can be used to treat peripheral neuropathy, such as peripheral neuritis, pain and numbness of nerves caused by diabetic patients, and so on. The adverse effects of this drug are very mild, with 1 in 1,000 people experiencing gastrointestinal irritation, nausea, vomiting, diarrhea, and less than 1 in 1,000 people experiencing an isolated skin rash. Overall, it does not cause significant harm to the stomach and can be taken with confidence. However, it must be noted that if you take this drug for more than one month and the symptoms of this neuropathy, such as pain and numbness, do not improve, you do not need to continue taking it.