Bacterial vaginosis (BV) is a common condition caused by a change in the normal balance of bacteria in the vagina. It is not considered a sexually transmitted infection, although sexual activity can influence the risk of developing BV.
Symptoms
Many people have no symptoms. When symptoms occur, they may include thin gray or white vaginal discharge and a strong fish-like odor, which may be more noticeable after sex. Itching or irritation can occur but is less typical.
Diagnosis and treatment
A healthcare professional can assess symptoms and may examine a sample of vaginal discharge. Symptomatic BV is commonly treated with antibiotics. Recurrence is common, and repeated symptoms should be reassessed rather than repeatedly self-treated because other conditions can cause similar symptoms.
When to seek medical advice
Seek medical advice for a new or persistent change in vaginal discharge or odor, especially during pregnancy, or if symptoms are accompanied by pelvic pain, fever, bleeding or pain during sex.
Sources and further reading
Last reviewed: 4 September 2026. This page provides general health information and does not replace individual medical assessment or treatment.