This case study highlighted key dietetic aspects in the management of a polymorbid oncology patient with kidney disease and high-stoma output and how these made significant contributions toward the patient’s clinical outcomes and quality of life. Studies have shown that ileostomy formation is independently associated with kidney injury due to an increased risk of dehydration through a high-stoma output. Treatment of high-output ileostomy includes correcting fluid, sodium depletion, and any other electrolyte abnormalities as well as appropriate pharmaceutical intervention.