Introduction: Congenital Glucose-Galactose Malabsorption (CGGM) is a rare autosomalrecessive defect present in infancy , caused by a gene mutation in the SLC5A1 gene, encoding the sodium-glucose cotransporter-1 (SGLT1). This impairment prevents intestinal absorption of glucose and galactose, leading to severe osmotic diarrhoea, lead to severe dehydration, metabolic acidosis, and death if left untreated. whereas fructose absorption via GLUT5 remainsintact in CGGM. Case Description: A 3-month-old, born to non-consanguineous parents, exclusively breastfed male presented with neonatalonset osmotic diarrhoea and profound failure to thrive (WAZ