Inclusion Criteria:

• HIV-negative
• Willing to participate and sign an informed consent
• Willing to be tested for HIV, use an experimental vaginal gel, and to be randomized to a study group that includes the possibility of being assigned to a placebo group.
• Willing to use two forms of contraception during the study.
• Willing to undergo pelvic examinations with colposcopy and photographic documentation according to the protocol throughout the study.
• Have a regular menstrual cycle defined as having a minimum of 21 days and a maximum of 36 days between menses.
• Willing to abstain from using any vaginal product (other than the study product or placebo).
• Willing to be sexually abstinent from randomization until completion of Day 7 evaluations.

Exclusion Criteria:

• Currently pregnant or breast-feeding.
• Clinically detectable genital abnormality on the vulva, vaginal walls or cervix.
• Laboratory confirmed gonorrhea, chlamydia, trichomonas, syphilis, or vaginal candidiasis or clinically diagnosed genital ulcer disease or active HSV-2 lesions.
• Breakthrough bleeding or gynecologic surgery within 60 days prior to randomization.
• Symptomatic bacterial vaginosis and unwilling to undergo treatment.
• Women who require treatment for tuberculosis (TB) within 21 days prior to randomization.