BACKGROUND Infantile hemangiomas are the most common benign tumors of childhood, occurring in approximately 5% of infants. Oral propranolol at 2 to 3 mg/kg daily is recommended for systemic treatment of high-risk infantile hemangiomas. Multiple propranolol formulations exist, and propranolol overdose can occur due to improper patient counseling. Propranolol acute toxicity in the pediatric population and its management are well described in the literature. However, data are lacking on chronic propranolol overdose and how to manage it, with the awareness that abrupt discontinuation of therapeutic doses of propranolol can lead to rebound sinus tachycardia. CASE REPORT A 7-month-old girl was prescribed a therapeutic dose of propranolol (1 mg/kg/day) to treat infantile hemangioma. However, due to an administration error, the patient received approximately 8 times the recommended dose (7.6 mg/kg/day for 2 months, then increased to 15.5 mg/kg/day for 2 weeks) and, surprisingly, remained asymptomatic. Her electrocardiogram was normal, and all routine laboratory tests were within the reference range. Propranolol was successfully tapered over 3 weeks by reducing the dose by 50% weekly until it reached the therapeutic dose. After tapering, the patient was asymptomatic, with a mild increase in hemangioma size. After 6 weeks of the therapeutic dose, the hemangioma was fading away. CONCLUSIONS This case is one of the few cases reported in the literature of high, chronic propranolol overdose in pediatric patients. The patient remained asymptomatic, and the overdose was successfully managed with gradual tapering over several weeks. This case report can serve as a guide in managing subsequent cases.