Poorly managed diarrhea may result in serious complications; therefore, comprehensive and standardized nursing care is essential. This study aims to describe the implementation of nursing care for children with gastroenteritis experiencing diarrhea as a primary nursing problem in the Delima Ward of Dr. Harjono Regional General Hospital, Ponorogo.

This research uses a case study approach with the nursing care process which includes assessment, determination of nursing diagnosis, planning, implementation, and evaluation. With the identity of the An.B patient, the data was collected through interviews, observations, and documentation studies on June 18, 2025 in the delima room of Dr Harjono Ponorog Hospital. The main nursing diagnosis raised is diarrhea associated with increased intestinal motility with the main intervention of diarrhea management

After conducting a nursing intervention that includes monitoring the frequency and consistency of feces, giving oral rehydration fluid, educating parents about diarrhea management, as well as observing signs of dehydration, it was obtained that the patient's defecation frequency decreased from 6 times to 2-3 times per day within 3 days of treatment. Fecal consistency improves, signs of dehydration are reduced, and parents show increased knowledge of diarrhea management. So on the third day the diarrhea nursing problem was solved.

Nursing care focused on monitoring fluid balance, family education, and supportive interventions have been proven effective in treating diarrhea in children with gastroenteritis. The implementation of systematic nursing care standards can help nurses in improving the quality of service and speeding up the patient's healing process.