Rationale: Dumping syndrome is a frequent and potentially severe complication after gastric surgery. Beinaglutide, a recombinant human glucagon-like peptide-1 (GLP-1) which shares 100% homology with human GLP-1(7-36), has never been reported in the treatment of dumping syndrome before.

Patient concerns: The patient had undergone distal gastrectomy for gastric signet ring cell carcinoma 16 months ago. He presented with symptoms of paroxysmal palpitation, sweating, and dizziness for 4 months.

Diagnosis: He was diagnosed with late dumping syndrome.

Interventions and outcomes: The patient was treated with dietary changes and acarbose for 4 months before admitted to our hospital. The treatment with dietary changes and acarbose did not prevent postprandial hyperinsulinemia and hypoglycemia according to the 75 g oral glucose tolerance test (OGTT) and continuous glucose monitoring (CGM) on admission.Therefore, the patient was treated with beinaglutide 0.1 mg before breakfast and lunch instead of acarbose. After the treatment of beinaglutide for 1 month, OGTT showed a reduction in postprandial hyperinsulinemia compared with before starting treatment, and the time in the range of 3.9 to 10 mmol/L became 100% in CGM. No side effect was observed in this patient during beinaglutide treatment.

Lessons: These findings suggest that beinaglutide may be effective for treating post-gastrectomy late dumping syndrome.