Acid-base disturbances can result from kidney or nonkidney disorders. We present a case of high-volume ileostomy output causing large bicarbonate losses and resulting in a non–anion gap metabolic acidosis. Non–anion gap metabolic acidosis can present as a form of either acute or chronic metabolic acidosis. A complete clinical history and physical examination are critical initial steps to begin the evaluation process, followed by measuring serum electrolytes with a focus on potassium level, blood gas, urine pH, and either direct or indirect urine ammonium concentration.