Bell's palsy is an acute unilateral paralysis of the facial muscles innervated by the seventh cranial nerve. Although the etiology of Bell's palsy is unknown, it is thought to result from edema, entrapment, or inflammation of the seventh cranial nerve. A history of recent viral infection--especially herpes simplex--diabetes mellitus, pregnancy, or hypertension are all common risk factors that may precede the onset. This article reviews assessment findings, differential diagnoses, and the treatment of Bell's palsy, which is considered a diagnosis of exclusion. A 10-day course of oral corticosteroids is the recommended therapy for lessening its course and severity in some populations. Recent research recommends the addition of acyclovir for 10 days, suggesting a herpetic viral etiology. Close follow-up is imperative to prevent corneal injury and to monitor worsening of symptoms. Although most patients recover within 1 to 6 months, incomplete recovery may be seen in severe or recurrent cases. Indications for referral are discussed. A case study is presented to illustrate the findings in this interesting disease.