The vascular complications of peritonsillar phlegmons have become exceptional. On the basis of a recent case, the authors sum up the criteria of severity, including: white puncture sample, paralysis of the 9th, 10th, 11th, 12th cranial nerves and of the cervical sympathetic nerve. Computed tomography allows not only refining the topographic diagnosis, but even sometimes diagnosing a pseudoaneurysm before it is fissured. At this stage, intraoperative radiology may probably prevent the unavoidable secondary rupture. If it cannot be used, preventive ligation must be proposed. In the absence of cataclysmic hemorrhage, this easier procedure usually does not cause any irreversible neurological deficit. If performed in emergency, it may entail a major risk, not only a neurological risk, but a vital risk as well.