Venous malformations (VMs) are rare, non-involuting, slow-flow, congenital anomalies of vascular morphogenesis, presenting as dilated venous channels with reduced perivascular cell coverage. The treatment may be conservative or surgical, including laser therapy. The management of small superficial VMs typically involves surgical excision. In larger or deeper VMs, the intralesional–endovascular injection of the sclerosing agent bleomycin is the gold standard, as it eliminates the dysplastic venous vessels by inducing fibrosis and therefore promotes regression of the lesion. This review explores the current literature regarding the role of bleomycin in venous malformation management, emphasizing the molecular pathways involved, the efficacy of sclerotherapy with bleomycin and its complications and the associated management challenges. It evaluates the clinical and histological features of venous malformations, alongside diagnostic methodologies and treatment strategies, drawing on the most recent bibliographic data. The literature was systematically reviewed using the PubMed database, offering insights into future research directions and highlighting innovative treatment approaches.