The most well known complications of fleet enema solution are cardiac insufficiency, renal failure, waterelectrolyte imbalance, and ileus. A 7-y-old girl with phenylketonuria and long-term constipation was admitted to the emergency department with symptoms of seizure, vomiting and abdominal distention. Laboratory results revealed hypocalcemia and hyperphosphatemia. ECG findings showed normal sinus rhythm and prolonged QT interval. At the followup, the patient's abdominal distention was markedly increased. She was evaluated for a surgical pathology and, this was considered unlikely. Intra-abdominal pressure (IAP) was 19.5 mmHg. Gastric and colonic decompression, intravenous 10 % calcium gluconate were applied. After 2 d of treatment, the patient's condition became stable, and serum calcium and phosporus normalized to 8.8 mg/dl and 4.0 mg/dl, respectively. Abdominal distention regressed and the last IAP measurement was 3.5 mmHg. Thus, IAP measurements are a useful adjunct in clinical follow-up of patients with progressive abdominal distention due to phosphate enema use.