Severe Hypocalcemia and Acute Respiratory Failure in a 3-Month-old Boy With ConstipationT o the Editor: We present a case highlighting how insufficient parental anticipatory guidance regarding administration of common over the counter laxatives may cause serious harm. A 3month-old boy with constipation presented to our emergency department with respiratory distress, lethargy, and emesis. The patient had metabolic acidosis (pH 7.2, CO 2 17, base deficit À6, anion gap 3), lactic acidosis (5.5 mmol/L), hypernatremia (156 mEq/L), hypokalemia (2.3 mEq/L), hypocalcemia (3.5 mg/dL), and hyperphosphatemia (9.6 mg/dL). He became apneic requiring endotracheal intubation. Brain computerized tomography scan revealed an aging germinal matrix hemorrhage without acute pathology.Our differential diagnosis included severe sepsis, inborn error of metabolism, impaired renal function, malabsorption, pancreatitis, tumor lysis, rhabdomyolysis, or unintentional intoxication. Days later, upon detailed questioning, the patient's father recalled administering Fleet enemas for constipation but unintentionally gave them orally. Ultimately, enteral uptake of exogenous phosphate caused systemic toxicity producing the presentation above. Reported cases of laxative-induced tetany are frequently noted in children with comorbid nephropathy or colonic dysmotility ( 1). Yet, a third are described in healthy children treated for constipation (1-4). After intravenous supplementation, our patient's metabolic derangements were corrected. He was extubated and 1 week later was discharged home without sequelae.Explicit anticipatory guidance for common over-the-counter medications is paramount. Providers must counsel families to administer laxatives as directed including dose, volume, route, and frequency. Caregivers should be given opportunities to vocalize understanding and provide simulated administration. Finally, abnormal laboratory data must be confirmed, assessed in clinical context, and with anticipation of potential sequelae that if untreated may be fatal.