Introduction: Gastroenteritis (GE) is one of the most common causes of emergency room visits, especially in pediatrics. The Canadian Paediatric Society and Choosing Wisely have issued high-grade recommendations to physicians working in the Emergency Department. It suggests, trying oral ondansetron followed by oral rehydration before installing venous rehydration in children with GE with adequate hydration or mild to moderate dehydration. This quality of medical care evaluation aims to determine if these recommendations were being applied for children aged 6 months to 12 years, with adequate hydration status or mild to moderate dehydration, who presented to the Chicoutimi emergency room between November 2016 and November 2018. Methods: Practice conformity was assessed according to two explicit criteria: prescription of oral ondansetron and appropriate mean of rehydration. A data collection tool was created and files were reviewed by investigators after standardization. Several secondary outcomes were assessed, including, among others, duration of symptoms, the number of vomiting and diarrhea. The hydration status was measured according to the capillary refill, feeling of skin to the touch, condition of buccal mucosa, tears, heart rate and mental status. These variables were analyzed to understand their impact on practice conformity. We excluded cases in which there was infections needing antibiotics, hypoglycemia, hemodynamic instability, no vomiting in the last 24 hours, convulsions and history of diabetes. Results: A total of 270 patient files were analyzed, 181 of which were included. Oral ondansetron was tried in 49 % of children. Rehydration was adequate in 55% of cases. The hydration level was written in 18% of files and the hydration status noted by the emergency room physician overestimated the dehydration score in 16% of cases. When hydration status was well assessed, adequate rehydration was observed in 63% of cases, while ondansetron was attempted in only 44% of cases. Conclusion: Use of oral ondansetron and adequate mean of rehydration to treat children aged 6 months to 12 years with GE in Chicoutimi emergency department is suboptimal. The difficulty of adequate dehydration assessment may be one of the causes. Concerted dehydration assessment grid and a group prescription for the administration of ondansetron during the nurse triage may constitute potential solutions.