What Is Bacterial Vaginosis?
Bacterial vaginosis (BV) isn't technically an STI—it's an imbalance of the normal bacteria in the vagina. Instead of the usual protective bacteria (like Lactobacillus), other bacteria overgrow and cause problems. It's super common: roughly 1 in 3 women of reproductive age experience it at some point.
What Causes It?
BV develops when the delicate balance of vaginal bacteria shifts. Common triggers include:
- New or multiple sexual partners (though BV isn't technically sexually transmitted)
- Douching (which disrupts natural bacteria)
- Antibiotics (which kill protective bacteria)
- Hormonal changes
- IUD insertion
Symptoms
Classic sign: A strong, fishy-smelling vaginal discharge that's usually grey or white. You might also notice:
- Itching or burning
- Discomfort during sex
- Pelvic discomfort
Important: About 50% of people with BV have no symptoms at all. It's often picked up during routine testing.
Testing
Your doctor or sexual health clinic can diagnose BV with a simple vaginal swab or by looking at vaginal fluid under a microscope. Testing is quick and straightforward.
Treatment
BV is treated with antibiotics, either as a cream, gel, or oral medication (metronidazole or clindamycin). Treatment usually takes 5–7 days and works well. Some people need a longer course or prophylactic treatment if BV keeps recurring.
Note: Partners don't usually need treatment, since BV isn't sexually transmitted. However, some partners may experience irritation from the bacterial imbalance, so communication helps.
Recurrent BV
Some people have BV that keeps coming back. If this happens, your clinic can discuss strategies like:
- Longer antibiotic courses
- Probiotics (evidence is mixed, but some people find them helpful)
- Regular monitoring
- Addressing triggers (like douching)
What If It's Left Untreated?
Untreated BV can increase your risk of pelvic inflammatory disease (PID) and complications during pregnancy. It's worth treating, especially if you're planning to conceive.
Prevention Tips
- Don't douche (your vagina is self-cleaning)
- Use barrier methods during sex to reduce bacterial exposure
- Avoid irritants like scented products
- Maintain overall sexual health through regular testing
Get Tested & Treated
BV is straightforward to diagnose and treat. If you have symptoms or concerns, Irish sexual health clinics and GPs can help. It's nothing to be embarrassed about—it's one of the most common things clinicians see.
If you are reading this about bacterial vaginosis — beyond the medicine
The medical bit is the easier half. The conversations, the anxiety, the partner notification, the privacy questions — those are where most people get stuck. These six pillar pages cover exactly that ground, in plain language and without judgment.
30-second self-check → · Telling a partner · Overcoming stigma
Or zoom out: the full hub · how testing works · symptoms — or not?
Where to next
You order directly from SH:24, which runs this service with the HSE. Free if you're 17 or over and live in the Republic of Ireland. Living in Northern Ireland?
Sources and limits
- HSE — Sexual health (free home STI testing eligibility; sexual health helpline number and hours)
- HSE — Sexual health services and clinics
Service details checked 10 September 2026. This page has not been reviewed by a named clinician and doesn't claim to have been. It explains how to reach services and what they publish — it isn't a diagnosis, and it can't replace talking to one.