The purpose of this study is to determine whether ME-609 is more efficient than acyclovir and placebo for the treatment of recurrent herpes labialis.

This was a randomized, double-blind, active- and vehicle-controlled study comparing the effects of ME-609, acyclovir in ME-609 vehicle, and vehicle alone. Treatment was subject-initiated within 1 hour of experiencing the first signs or symptoms of a herpes recurrence. The subject visited a study clinic as soon as possible after treatment initiation, but no later than midnight of the following day, for evaluation.

Inclusion Criteria:

• Generally good health
• History of recurrent herpes labialis with at last three episodes during the prior 12 months

Exclusion Criteria:

• Treatment with antivirals or immunosuppressive agents within 2 weeks prior to randomization
• Pregnant and/or nursing women
• Continuous daily treatment with pain medication
• Significant skin condition that occur in the area of herpes recurrences