Current drug treatment of Bell's palsy often consists of prednisone for patients with a complete paralysis. Since it was demonstrated that herpes simplex plays a role in the pathogenesis of Bell's palsy, antiviral therapy may become the treatment of choice. Six randomized controlled trials comparing prednisone with placebo have been performed: four of them did not conform to the criteria for good clinical trials. The remaining two trials did not demonstrate therapeutic efficacy of prednisone. A recently published randomized controlled trial comparing prednisone and acyclovir with prednisone and placebo showed a statistically significant and clinically important superiority of the combination therapy. This trial, however, also had methodological flaws and its results should be interpreted with caution. In our opinion, further evidence is needed before acyclovir should be given routinely to patients with Bell's palsy.