A 20-year-old man with bulimia nervosa and chronic kidney disease stage G3aA2, whose serum creatinine level was 1.5-1.6 mEq/L, was referred to the nephrology clinic for evaluation of refractory hypokalemia. The hypokalemia had been previously attributed to chronic vomiting since age 15. He was still reporting episodes of vomiting but denied chest pain, shortness of breath, abdominal pain, diarrhea, or urinary symptoms. The patient also denied using over-the-counter medications. Home medications included potassium chloride 60 mEq 4 times daily and magnesium oxide 400mg 3 times daily.