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Bacterial Vaginosis

Bacterial vaginosis isn’t a sexually transmitted infection. It is an imbalance of the usual bacteria found in a woman’s vagina that affects women and can cause an abnormal vaginal discharge which can smell fishy and unpleasant.

How it develops

Bacteria called lactobacilli naturally live in your vagina and stop other bacteria from growing there. It’s not fully understood why, but sometimes the balance of these bacteria changes. If this happens you can develop bacterial vaginosis in this condition, bacteria other than lactobacilli overgrow in the vagina and usually cause symptoms.

Bacterial vaginosis can’t be passed from person to person but it is more common in people who are sexually active

Other things that may increase your risk of getting it include:

  • Having a new sexual partner
  • Having multiple sexual partners
  • Smoking
  • Using scented soaps or perfumed bubble bath
  • Putting antiseptic liquids in the bath
  • Douching (washing or cleaning out the vagina with water or other fluids)
  • Using vaginal deodorant
  • Using strong detergents to wash your underwear


Often there are no symptoms of bacterial vaginosis, but some women may notice a change in the normal discharge from the vagina.

This discharge will usually be white or grey, thin or watery and have a strong, unpleasant fishy smell, which can be more noticeable during and after sex, and during periods.

Bacterial vaginosis does not usually cause itching or irritation.


If you are worried that you may have bacterial vaginosis, visit your GP or sexual health service. The nurse or doctor may use a swab to collect a sample of the discharge from your vagina.

A swab looks a bit like a cotton bud and collecting a sample only takes a few minutes. Although not painful, it may be a little uncomfortable for a moment. A specially coated paper may be used to test the pH (alkaline/acid balance) of your vagina.

Sometimes a diagnosis can be made straightaway because of the distinctive appearance of the discharge or sometimes the sample will be sent to a lab for testing.

If the doctor suspects you may have an STI they may do more tests.


Bacterial vaginosis is treated with antibiotics. An antibiotic cream or gel to use in the vagina may be given instead of antibiotic tablets by mouth.

There is currently no evidence that probiotics, such as those found in live yoghurt, are of any benefit for treating or preventing bacterial vaginosis.

You can still have sex whilst you are being treated for bacterial vaginosis because it is not sexually transmitted, however antibiotics and cream can affect condoms and other contraception so speak to your doctor or pharmacist who can give you more information.

Whilst you're there, make sure you tell the doctor or nurse if you are pregnant or think you might be, or if you are breastfeeding - it may also affect the type of treatment you are given.

Partners do not usually need treatment.


The causes of bacterial vaginosis are not fully understood, so it may not be possible to completely prevent it. However, you may be able to lower your risk of developing it by:

  • Not using scented soaps and perfumed bubble bath
  • Not using vaginal deodorant
  • Not douching (washing or cleaning out your vagina)
  • Not putting antiseptic liquids in the bath
  • Not using strong detergent


For more information call  0800 22 44 88 or use our sexual health service finder to look for help in your area.