We plan to conduct a randomized controlled trial of chronic suppressive acyclovir, 400 mg orally twice daily (standard dose) versus episodic acyclovir for treatment of genital herpes recurrences. We will enroll 500 HSV-2 seropositive single persons (250 per arm), stratified by gender and history of symptomatic genital herpes, and prospectively follow them for 1 year to assess sexual behavior, adherence to therapy, and herpes-related quality of life. These outcomes will be measured by self-report in a confidential, computer-based assessment. We plan to use data from this trial to model the effect that increasing the proportion of sexually-active HSV-2 infected persons taking suppressive therapy will have on population-level incidence and prevalence of HSV-2.