Background <p>Early oral propranolol for infantile hemangioma (IH) can improve the success rate. However, few studies have been conducted on the specific age threshold for initiating treatment with propranolol. This study aimed to determine the cutoff value of treatment success for IH with oral propranolol.</p> Methods <p>This was a retrospective study involving 207 patients with IH and clinical data.The primary outcome measure was treatment success with oral propranolol at months 6 to 12.</p> Results <p>Multivariate analysis showed that age at treatment initiation (<i>P</i> &lt; 0.001), high-risk IH (<i>P</i> = 0.002), and segmental IH (<i>P</i> = 0.012) were independent risk factors for treatment unsuccess with oral propranolol at months 6 to 12. Receiver operating characteristic (ROC) curve analysis indicated that the cutoff value for age at treatment initiation was 69.5 days for all patients, 65.5 days for patients with segmental IH or high-risk IH, and 93.5 days for patients with non-high-risk and nonsegmental IH. Patients who started treatment before 69.5 days had a success rate of 73.8%, which was higher than the 28.4% success rate of patients who started treatment after 69.5 days. The median time to treatment success for patients who started treatment before 69.5 days was 11.5 months, which was shorter than the 15 months for patients who started treatment after 69.5 days.</p> Conclusion <p>The initiation of treatment for IH with oral propranolol before 70 days of age can improve the success rate and shortens treatment duration, especially for segmental IH and high-risk IH.</p> Clinical trial number <p>Not applicable.</p>