The study will enroll men and women who are 18 years or older, test positive to HSV-2 (by blood test) and have had a first outbreak of HSV-2 within the past 6 months or have had at least 4 genital herpes outbreaks in the past year. Participants must be HIV negative and willing to stop taking suppressive therapy for HSV for the one week wash out period. (Females only: You must not be pregnant or breast-feeding). Both men and women will be asked to use an effective form of birth control.