Functional fecal retention is the most common cause of encopresis in children. Hospitalization may be required to clear the bowel following failure of outpatient management. Although the safety and efficacy of polyethylene glycol electrolyte solution is well established in children older than 6 months (1), its use should be carefully monitored in patients with altered mental status or impaired airway protective reflexes. We report the accidental infusion of NuLytely into the lungs of an 11-year-old female patient who consequently developed life-threatening acute lung injury. She rapidly developed respiratory failure requiring emergent tracheal intubation and suctioning, followed by mechanical ventilation. Careful monitoring is needed to avoid this potential complication if polyethylene glycol solution is infused via a nasogastric tube.