Bacterial vaginosis (BV)

What is it?

Bacterial vaginosis is a common cause of vaginal discharge in women. It is not actually a sexually transmitted infection.

How do I catch it?

You do not "catch" bacterial vaginosis as it is not a sexually transmitted infection.

In women with BV, there is normally less of the friendly vaginal bacteria (lactobacilli), an overgrowth of unfriendly bacteria and a change in the vaginal pH (acid/alkaline balance), which becomes more alkaline. It is not clear what causes the reduction in friendly bacteria.

BV can be triggered by using scented soaps, shower gel or bubble bath, putting antiseptic liquids in the bath, spraying water inside the vagina or using vaginal deodorant. Hormone changes during the menstrual cycle and semen in the vagina after unprotected sex may also play a part.


The symptoms of BV are an increase in the amount of vaginal discharge, which often has an unpleasant smell.


BV is diagnosed by looking at a sample of vaginal discharge under the microscope in the clinic.


Bacterial vaginosis can be treated with antibiotics. This is usually given as a course of tablets, but may sometimes be given as a cream or gel to use inside the vagina.

See the FPA website for a range of downloadable leaflets on contraception and sexually transmitted infections.

View FPA leaflets

The British Association for Sexual Health and HIV (BASHH) website also features a range of downloadable leaflets on STIs.

View BASHH leaflets