– L-Glutamic acid monosodium salt monohydrate (MSG monohydrate) is an important food additive with gastrointestinal protective effects. It plays a critical role in nutrient metabolism, energy demand, immune response, oxidative stress, signal transduction, and synaptic transmission. L-Glutamic acid monosodium salt monohydrate can induce oxidative stress, DNA damage, and apoptosis in mouse liver and brain tissues. It can protect against gastrointestinal damage caused by NSAIDs and Helicobacter pylori through multiple mechanisms.