Infantile hemangiomas undergo rapid growth during early infancy followed by gradual involution. Infantile hemangiomas sometimes impair vital functions or cause disfigurement. Thirty-two Japanese patients between the ages of 1 and 4 months with proliferating infantile hemangiomas received oral propranolol on an outpatient basis. The success rate (complete or nearly complete resolution) at week 25 was 56% (18/32). Two patients dropped out because of a personal reason and moving out. Recurrence after termination of treatment was seen in six patients. Adverse events occurred in 16 patients. There were no adverse events on day 1 (initiation of treatment at a dose of 1 mg/kg per day) and day 8 (dose increase to 2 mg/kg per day). One patient was hospitalized due to pneumonia, and suspended propranolol for 26 days. Oral propranolol at 2 mg/kg per day is effective and safe in Japanese patients with infantile hemangiomas.