Patients are randomized in a 2:1 ratio to receive either Valtrex or placebo, twice daily, for up to 6 months. Patients come to the clinic for routine monthly assessments for 6 months, and return to the clinic for evaluation within 24 hours of the first signs or symptoms of an ano-genital HSV recurrence. Once the clinician confirms the presence of at least the macular/papular lesion stage, double-blind suppressive therapy is discontinued and open-label treatment with a higher dose of Valtrex twice daily for 5 days is initiated. For the first recurrence, patients are instructed to return to the clinic for further clinical assessments on Day 5 of the recurrence. Patients who have not healed by Day 5 may be offered an additional five days of open-label treatment, as deemed appropriate by the clinical investigator. If an additional 5-day course of open-label treatment medication is dispensed, the patient returns to the clinic on Day 10 for evaluation. Patients who have not healed by Day 10 are managed as deemed appropriate by the investigator. Once treatment of the first ano-genital HSV recurrence is complete and the patient is healed, patients are switched to open-label suppressive therapy with Valtrex for the remainder of the study period (up to a maximum of 6 months). The total duration of the study for all patients is 6 months.