A patient presented with transaoral hemorrhage for 3 weeks after mandibular osteotomy. Angiographic evaluation showed a pseudoaneurysm of the internal maxillary artery (IMA). Superselective transcatheter arterial embolization of the neck of the pseudoaneurysm was performed by liquid adhesive suspension, and bleeding was arrested with the preservation of the parent artery. Vascular injury at the mandibular osteotomy site is rare but can occur. Transcatheter arterial embolization by liquid adhesive suspension was a prompt and effective solution. (Tzu Chi Med J 2003; 15:191-194)