A retrospective cohort study compared the efficacy of urea, bleomycin, and polidocanol in the treatment of 234 cases of infantile hemangiomas (IH) in infants aged 0–3 years. Treatment included two courses of sclerotherapy 4 months apart between January 2000 and Polyclinic B until 2025. Bleomycin achieved the highest efficacy with a 40% complete response (CR) rate at 6 months and no non-responders. Urea showed 33% CR at 6 months with gradual improvement, polidocanol 25% CR with variable efficacy. Decreases in the degree of blood flow measured by ultrasound were strongly correlated with better outcomes (p < 0.05), but changes in vascular proliferation were not. No significant adverse events were reported. The study recommends monitoring the degree of blood flow by ultrasound as a predictor of success and emphasizes the need for prospective studies due to the risk of bias.