In a series of 1502 patients seen in our Facial Paralysis Research Clinic 1048 were diagnosed as having Bell's palsy. Review of clinical, epidemiologic, and laboratory data, plus review of the literature, has led to the conclusion that Bell's palsy is an acute benign cranial polyneuritis probably caused by reactivation of the herpes-simplex virus, and the dysfunction of the motor cranial nerves (V, VII, X) may represent inflammation and demyelinization rather than ischemic compression. Spinal fluid analysis suggests that the disease is a phenomenon of the central nervous system with secondary peripheral neural manifestations. With our presently available information, treatment of a viral disease with an anti-inflammatory agent is rational. Prednisone treatment started within the first week of the disease can restore better function to the paralyzed face than is achieved without such therapy, and facial nerve decompression has been unnecessary.