Updated January 2014


Bacterial Vaginosis (BV) is a type of vaginal infection that occurs when there is an imbalance in the normal bacteria found in the vagina.


A number of different organisms live in a healthy vagina. Some bacteria, like lactobacillus, are considered good bacteria and others harmful bacteria.  BV can develop when there is an overgrowth of harmful bacteria.

BV is not considered a sexually transmitted infection (STI), but it is more common in women who have had sexual intercourse. Not much is known about how women get BV or how to prevent it. However, there are certain factors that can put a woman at increased risk of BV including having a new sexual partner, having multiple sexual partners and douching.  A woman can have BV even if she has never been sexually active.

Signs and Symptoms

Women with BV may notice a greyish-white or milky discharge with an unpleasant or fishy odour, especially after sex. Less commonly women may also have itching or burning in or near the vagina, burning with urination or burning during intercourse. However, most women have no symptoms.

Diagnosis and Tests

If a woman has symptoms, a doctor or nurse can perform an exam to look for signs of BV and collect a swab of the vaginal discharge to diagnose the infection.


BV itself is not harmful, but it has been associated with some health risks.

Research shows:

  • a link between BV and Pelvic Inflammatory Disease (PID). This is when the infection can spread to the uterus and fallopian tubes. The risk of PID is higher after an IUD insertion, abortion or other gynaecological surgeries
  • a link between BV and an increased risk of spreading HIV or becoming HIV positive if you are exposed to HIV.
  • a link between BV and increased risk of getting other STIs such as Chlamydia, gonorrhea and herpes if you are exposed to these infections
  • in pregnancy, a link between BV and premature birth or early breaking of the amniotic sac (your waters)


If you have BV and symptoms, your healthcare provider will probably treat you with antibiotics. Male partners do not require treatment. The most common medication used is called metronidazole (Flagyl). Some people may feel nauseated or have diarrhea when taking this medication, while others may notice a dry metallic or bitter taste in their mouth. You should not drink alcohol (beer, wine or liquor) during treatment and for 24 hours afterwards. Alcohol and metronidazole taken together can cause severe nausea and vomiting. If you have no symptoms of BV, treatment is usually not recommended except in special situations.

If you are pregnant or breastfeeding, talk to your healthcare provider before taking any medication.

BV can come back after treatment. It can also sometimes clear up without treatment.

Prevention/Self-care Tips

It is important to keep your vagina healthy. Your vagina cleans itself. It is only necessary to clean the outer genital with warm water.

  • Don’t use feminine hygiene sprays or wash with soap inside the vagina.
  • Don’t douche unless your doctor recommends it. Douching increases your chance of getting BV. It changes the normal acid balance in the vagina.
  • Limit the number of sexual partners you have.
  • Use condoms correctly every time you have sex to lower your chance of getting an STI.

Information for Sexual Partners

Men cannot get BV and treatment is not recommended for male sexual partners. However, BV may spread between female sexual partners.

More Information

Call the Sexual Health Infoline Ontario at 416-392-2437 or 1-800-668-2437

Safer sex: To reduce your risk of getting a sexually transmitted infection (STI), use a condom every time you have vaginal, anal or oral sex.