Bell's palsy is defined as a facial nerve paralysis without any other known diagnosis or cause .Its' estimated occurrence is in 20 to 30 people per 100,000 people per year. The occurence is greater in patients older than 65 years old and lower in children younger than 13 years old. There are many estimated etiologies for Bell's palsy, such as failure of the vasa nervosa, viral infections, ischemic neuropathies and auto immune reactions. Of those, viral hypothesis is the most widely accepted.