Inclusion Criteria:

1. Age 18-45 at time of enrollment.

2. Recurrent BV as defined by:

   • 2 previously documented diagnoses of BV in the past 6 months or
   • 3 previously documented diagnoses of BV in the past year
3. Non-pregnant, non-lactating.
4. Premenopausal.

5. Presence of bacterial vaginosis at the enrollment visit using Amsel Criteria (at least 3 of 4):

   • Presence of homogenous vaginal discharge
   • pH of vaginal secretions of > 4.7
   • Presence of a positive "whiff" test of the vaginal secretions upon mixing with 10% KOH
   • Presence of > 20% clue cells on saline microscopy
6. Willingness to undergo randomization to a possible placebo arm (for suppressive therapy).
7. Ability to undergo informed consent.
8. Willingness to refrain from use of any intravaginal products (including douching, contraceptive spermicides, creams, gels, foams).
9. Currently using an acceptable method of birth control (such as a hormonal method including oral contraceptives, Depo Provera, Ortho Evra, abstinence x 60 days, consistent condom use, surgically sterile, lesbian orientation).
10. Willing to refrain from alcohol consumption during use of study medication and three days following completion of medication (which includes the 10 day open label treatment and the entire 3 month suppressive phase of treatment).

Exclusion Criteria:

1. Known active sexually transmitted infection at the time of enrollment with C. trachomatis, N. gonorrhoeae, T. vaginalis, or active (symptomatic) vulvovaginal candidiasis.
2. Current use of anticoagulants/blood thinners (i.e. warfarin, coumadin, heparin).
3. Current use of any of the following medications: lithium, fluorouracil, anticonvulsant/seizure medications, Questran (cholestyramine) or CYP3A4 inducer/inhibitors (i.e. phenobarbital, rifampin, phenytoin, fosphenytoin).
4. Use of Antabuse (disulfiram) currently or within the past 2 weeks.
5. Allergy to metronidazole or tinidazole (related drugs with likely cross-over allergy potential).
6. Use of any antibiotics (oral or vaginal) in the past 7 days.
7. Current use of an IUD, Nuva Ring.
8. Known immunosuppressive condition (i.e. HIV, end-stage renal disease, currently-treated diabetes mellitus, etc.) or on immunosuppressive medications [i.e. steroids, cyclosporine, Protopic (tacrolimus), immunomodulators].
9. Participation in an investigational drug study within the past 30 days.
10. Any condition which in the opinion of the investigator would impose a health risk to the subject or interfere with the evaluation of the study medication or procedures.