Source partners who have a recurrence of genital HSV while on the study will be asked to have their lesions cultured and will be offered open-label valaciclovir treatment. Susceptible partners who contract genital herpes from the source partner during the study will have a genital examination to verify a fist episode of genital herpes and will receive 10 days of open-label treatment with valaciclovir. Cultures will be taken from the mouth and genitals, current medical conditions will be reviewed, blood samples will be drawn on treatment days 1 and 10, and treatment side effects will be reviewed on days 5 and 10.