Glutamine capsules are recommended to be taken after meals. The main ingredient of glutamine capsules is glutamine, an amino acid drug. Glutamine capsules are commonly used clinically to treat gastric ulcer and duodenal ulcer and to improve patients’ symptoms such as abdominal pain, bloating, acid reflux and belching. Pharmacological studies have proved that glutamine has a significant repairing effect on gastrointestinal mucosal damage, a promoting effect on normal gastric mucosal defense factor production, and a promoting effect on the formation of healing granules of gastric and duodenal ulcers. Since glutamine capsules have gastrointestinal adverse effects such as nausea, constipation, diarrhea and vomiting, patients are advised to take glutamine capsules after meals, which can alleviate gastrointestinal symptoms.