Patient description: The patient is a 47-year-old Asian woman complaining of persistent feelings of sadness. She lost interest in activities she used to enjoy. She states that her mood is mostly depressed for the past 3 weeks. She also lost her appetite , which led to about 5kg weight loss. She complains of loss of energy and feelings of worthlessness nearly every day. She is not using any drugs and she does not smoke. She doesn't drink alcohol. She used to exercise every day for at least 30 min. But she doesn't have enough energy to do so for the past 3 weeks. She also has some digestive issues recently. She is married and has 4 children. She is menopausal. Her husband was recently diagnosed with colon cancer and he is starting his chemotherapy. There is nothing remarkable in her past medical history and her drug history is only positive for Vit D3 1000 units daily. Her family history is negative for any psychologic problems. Her HAM-D score is 20.

Clinical trial eligibility criteria: eligible ages (years): 16.0-50.0,  Bacterial Vaginosis Women will be included whether their complaint is symptoms of BV and have a positive whiff test/vaginal swab or if they have a positive whiff test/vaginal swab and are then asked if they have any symptoms of BV present. The following must be met for enrolment in the study: 1. ages 16-50 and premenopausal; 2. capable of giving written informed consent; 3. English speaking; 4. negative pregnancy test on enrolment day; 5. agree to follow study protocol; 6. documented BV infection by positive vaginal swab +/ positive whiff test/pH > 4.5; 7. agree to no intercourse for the 10 days of treatment (or to use non-lubricated condoms if unavoidable); 8. agree not to douche or use any intravaginal products during treatment (including tampons, medications, devices); 9. abstain from alcohol during the 10 days of treatment (from 24 hours before through 72 hours after taking study medication); 10. agree to no new medications or antibiotics during treatment; 11. no current sexually transmitted infection as determined by history, physical exam and negative swabs for chlamydia, gonorrhea, candidiasis, trichomonas; 12. patient is reliable for follow up  The following women would be excluded from study participation: 1. less than 16 or post-menopausal; 2. negative vaginal swab regardless of whiff test/pH > 4.5; 3. menstruating at diagnosis; 4. symptoms so severe as to make allocation to placebo unacceptable to the patient; 5. currently pregnant or at high risk for pregnancy; 6. current sexually transmitted infection (HIV, hepatitis, chlamydia, gonorrhea, trichomonas, HPV or HSV); 7. current yeast infection as determined by history, physical and swabs; 8. history of PID; 9. allergy to latex or metronidazole; 10. presently lactating; 11. any open wound, excoriation, vaginal irritation and including bartholin's cyst/abscess as determined by physical exam; 12. presence of another vulvar, vaginal or medical condition, including cervical neoplasia treatment, that might confound treatment response; 13. using lithium, anti-coagulants or disulfiram drugs; 14. any antifungal or antibiotic use 14 days prior to enrolment 15. PAP smear done within one week of enrollment