Bacterial Vaginosis

Comments from Expert Advisory Group

  1. Bacterial Vaginosis (BV) is a common cause of abnormal vaginal discharge in women of reproductive age. It is not considered to be sexually transmitted.
  2. It is characterised by a white, non-irritating, malodorous vaginal discharge. The discharge commonly smells "fishy" and this odour is often more noticeable after sexual intercourse.
  3. The diagnosis can be made clinically on the basis of the description and appearance of the discharge. Typically the normal pH of the vagina is increased from normal (<4.5) to above 4.5 and up to 6.0 reflecting the replacement of normal lactobacilli with anaerobic organisms. Treatment can be started without doing a high vaginal swab (HVS).
  4. A HVS is indicated when assessing abnormal vaginal discharge but is not part of an asymptomatic STI screen. Gram staining from a HVS in people with BV will demonstrate changes in the normal vaginal flora. A diagnosis of BV should not be made solely on demonstration of changes in the vaginal flora consistent with BV and / or the presence of organisms associated with BV (e.g. Gardnerella species) on a HVS.
  5. It is important to establish the risk of a sexually transmitted cause of vaginal discharge on the basis of sexual history. Further information is available from An Approach to an STI Consultation in Primary Care.
  6. There is no benefit in treating male partners. Consideration should be given to assessment of partners of women who have sex with women (WSW).
  7. For women experiencing repeated episodes of bacterial vaginosis:
    • Reconsider diagnosis, including further examination as appropriate.
    • Check continued exposure to contributing factors (unprotected sexual intercourse, vaginal douching, smoking. Further information is available in the Bacterial vaginosis patient information leaflet.
    • Consider adherence with initial treatment.
    • Women may benefit from using lactic acid vaginal gels to facilitate restoration of the normal vaginal flora. Preparations are available over the counter in pharmacies.


Drug Dose Duration Notes
1st choice options

Metronidazole oral


400mg every 12 hours



5-7 days



Advise patients to avoid alcohol during metronidazole therapy and for at least 48 hours after stopping.


Clindamycin 2% cream





5g applicatorful inserted intravaginally at night





7 nights






Avoid clindamycin cream in 1st trimester of pregnancy.

Clindamycin cream can weaken latex condoms/diaphragms, which should not be used during treatment and for 72 hours afterwards.

Avoid clindamycin cream in those with a history of inflammatory bowel disease or a history of antibiotic-associated colitis.

2nd choice option
Clindamycin capsules 300mg orally every 12 hours 7 days Caution: Risk of C. difficile infection.
Pregnancy: Metronidazole is the treatment of choice in pregnancy. Intravaginal clindamycin cream should be avoided in first trimester.

Patient Information

Safe Prescribing

Visit the safe prescribing page

Reviewed April 2024

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