Facial pain, which is sometimes extremely severe, may be caused by either intracranial or extracranial conditions. The latter include dental disease, tumors or infected cysts of the mandible, disturbances about the temporomandibular joint, lesions involving nasal accessory sinuses and other paranasal structures, elongated styloid process, nasopharyngeal tumors, tumors involving the trigeminal ganglion and nerve, acoustic neurinomas or cerebellopontine angle meningiomas, and aneurysms or anomalies of certain arteries. The best known clinical syndrome marked by facial pain is trigeminal neuralgia. Treatment by root section generally gives relief of pain, but the price that patients pay for complete relief is total anesthesia in the corresponding area. A medical treatment takes advantage of the unusual neurotropic action of stilbamidine isethionate. Injected intravenously, this drug produces a trigeminal neuropathy consisting of hypesthesia and paresthesia but no motor paralysis. This action is slow but prolonged. The paresthesias are troublesome in about 20% of the cases but are usually selflimited. Since this drug action affects only the fifth nerve, careful differential diagnosis is essential in order to preclude futile treatment of atypical neuralgias involving the seventh and ninth nerves.