Vascular malformations are frequent in the head and neck. In addition to the occasional devastating cosmetic effects of large vascular malformations, some may cause significant functional impairment by encroaching on the eye, tongue, or throat. Large lesions may produce a breakdown of skin or mucosa, with resultant leakage of blood or fluid and possible infection in the lesions and surrounding tissues. Arteriovenous malformations, in particular, may develop massive bleeding spontaneously or with minor trauma. Numerous treatment options are available for treatment of these lesions. Surgical excision is the traditional treatment for vascular malformations in the head and neck. However, some lesions may be difficult to remove when they permeate and envelop normal structures, such as the facial nerve, and a less invasive mode of therapy may prevent damage to these normal structures. Percutaneous sclerotherapy was developed as a minimally invasive treatment modality for these lesions. It has also proved helpful as a preoperative adjunctive treatment of these lesions to reduce surgical blood loss and to delineate the surgical extent of resection.