Eligible subjects will be randomized to receive VALTREX 1g or placebo once daily for 60 days in a two-way crossover study with a washout period of 7 days in between.

Inclusion Criteria:

• Subject is in overall general good health.

• If female, subject must be of:

  1. Non-childbearing potential (i.e., physiologically incapable of becoming pregnant, including any female who is pre-menarchial or post-menopausal or surgically sterile); or
  2. Childbearing potential, but must have a negative pregnancy test at randomization, and must be compliant with one of the following: Complete abstinence from intercourse for two weeks before exposure to the study drug, throughout the clinical trial, and for a period of 1 week after study completion or premature discontinuation from the study (to account for elimination of the drug); Have a male partner who is confirmed to be sterile prior to the female subject's entry into the study and is the sole sexual partner for that female subject; Use of contraceptive(s) with a documented failure rate of less than 1% per year, including but not limited to: implants of levonorgestrel, use of injectable progestogen, oral contraceptives (either combined or progestogen only), an intrauterine device (IUD) or spermicide plus a mechanical barrier (condom/diaphragm).
• Subjects must be newly diagnosed with a first recognized episode of genital herpes as described in (a) or (b) below (See Appendix 3): a.HSV-2 seropositive at screen, with documented clinical signs and symptoms consistent with genital herpes at screen or within 4 months prior to randomization or b.HSV-2 seronegative at screen, AND HSV-2 culture positive or HSV-2 PCR positive with documented clinical signs and symptoms consistent with genital herpes at screen or within 4 months prior to randomization.
• Subject must be willing and able to provide written informed consent and comply with the protocol.

Exclusion Criteria:

• Subject is known or suspected to be immunocompromised (e.g., subjects receiving immunosuppressive therapy or chemotherapy for malignancy, or are seropositive for HIV).
• Subject received an investigational drug in the 30 days prior to the randomization visit.
• Subject is receiving systemic antiviral or immunomodulatory treatments.
• Subjects who have received systemic antiherpetic treatments (e.g., valacyclovir, acyclovir, ganciclovir, famciclovir) within 3 days of starting study drug, or immunomodulatory treatments in the 30 days before starting study drug.
• Subject has clinically significantly impaired renal function as defined by creatinine clearance less than 50ml/min (calculated using the Cockcroft-Gault formula).
• Subjects with a history or evidence of decompensated liver disease, or clinically significantly impaired hepatic function defined as an ALT (alanine transaminase) level >3 times the normal upper limit.
• Subject is known to be hypersensitive to valacyclovir, acyclovir, ganciclovir or famciclovir.
• Subject has malabsorption or vomiting syndrome or other gastrointestinal dysfunction that may impair drug pharmacokinetics.
• Female subject who is contemplating pregnancy within the duration of the study drug dosing period.
• Female subject who is pregnant and/or nursing.
• Subject with current alcohol or drug abuse.
• Subjects who have received suppressive (daily) therapy for genital herpes prior to randomization. Suppressive therapy is defined as daily antiherpetic therapy of at least 4 weeks duration.
• Subjects with a history of ocular HSV (herpes simplex virus) infection.