Written for Stock My Medicine and clinically reviewed by Hajra Dhanchora, MPharm (GPhC 2216990).
Bacterial vaginosis is the most common cause of unusual vaginal discharge in women of childbearing age, more common than thrush, and most people have never heard of it until they have it. It's not an infection you catch and it's not a hygiene problem; it's the balance of the vagina's own bacteria tipping the wrong way. The good news is it's easy to treat. The frustrating news is it likes to come back. Here's how to recognise it, how to treat it from the pharmacy, and what actually keeps it away.
BV symptoms
The one symptom that matters: a thin, watery, greyish-white discharge with a fishy smell, often stronger after sex and during a period. There's usually no itching, no soreness and no pain, which is the clue that it isn't thrush. Around half of women with BV have no symptoms at all and only find out from a swab. BV doesn't cause pain when you pee, bleeding or pelvic pain; those point elsewhere and need checking.
Is it BV or thrush?
| Bacterial vaginosis | Thrush | |
|---|---|---|
| Discharge | Thin, watery, grey-white | Thick, white, like cottage cheese |
| Smell | Fishy, worse after sex | Little or none |
| Itching and soreness | Usually none | The main complaint |
| Cause | Bacterial imbalance, pH too high | Yeast (candida) overgrowth |
| Pharmacy treatment | Lactic acid gel or pessary | Clotrimazole or fluconazole |
Treating BV with thrush cream does nothing, and vice versa, so getting this right saves a week. If you're not sure, a Canestest self-test swab reads vaginal pH in seconds: a raised pH suggests BV, a normal one with symptoms suggests thrush. Our thrush guide covers the other side.
What causes BV?
A healthy vagina is kept slightly acidic by lactobacilli. When they fall and other bacteria take over, the pH rises and the smell and discharge follow. What tips the balance: sex (semen is alkaline; a new partner or several partners raises the risk, though BV isn't a sexually transmitted infection), periods (blood is alkaline too), douching, perfumed washes, bubble bath and scented wipes, a copper coil, smoking, and antibiotics taken for something else. You can't get BV from toilet seats, swimming pools or bedding, and men can't catch it, although female partners can share it.
How to treat BV from the pharmacy
For mild or first-time BV, and for the familiar early signs of a recurrence, a lactic acid gel restores the acidity the lactobacilli need and clears symptoms in most women within a few days.
| Product | How it's used | Notes |
|---|---|---|
| Balance Activ BV Gel | One applicator tube at bedtime for 7 nights | The best-known; a 14-day pack covers treatment plus prevention. Safe in pregnancy. |
| Balance Activ BV Pessaries | One pessary at bedtime for 7 nights | Same job without the gel; some prefer it for less leakage. |
| Canesbalance | One tube daily for 7 days | Lactic acid with glycogen to feed the good bacteria; also as pessaries. |
| Relactagel | One tube at bedtime for 7 nights | Lactic acid and glycogen; often used after a period to prevent a flare. |
All of these are suitable in pregnancy and breastfeeding, and none interacts with other medicines. Avoid sex, or use a condom, during the course, and don't use a lactic acid gel at the same time as a thrush pessary; do one, then the other. Everything above is in our thrush and intimate health collection.
When BV needs antibiotics
If symptoms are severe, haven't cleared after a week of gel, keep returning, or you're pregnant, see a GP or a sexual health clinic. They'll confirm BV with a swab and usually prescribe metronidazole, as a 7-day course of tablets or a vaginal gel; clindamycin cream is the alternative. No alcohol with metronidazole tablets or for 48 hours after, because the combination makes you sick. Antibiotics clear BV in about 90% of cases, but a third of women see it back within three months, which is where the prevention section earns its keep. For four or more episodes a year, a GP may suggest a longer course of metronidazole gel twice a week for several months.
Why BV keeps coming back, and how to stop it
- Wash with water only, or a plain unperfumed wash, and only the outside. The vagina cleans itself; soap inside it strips the lactobacilli.
- No douching, no scented wipes, no bubble bath, no "feminine" sprays. This is the single biggest cause of recurrence.
- Use a preventive course of lactic acid gel for three nights after each period, and after sex if that's your trigger. It's cheaper than another week of treatment.
- Condoms keep semen's alkalinity away; if BV follows sex with one partner, this often solves it.
- Cotton underwear, no tight synthetics, and change out of wet swimwear.
- Stop smoking; smokers get BV more often and it recurs more.
- Treat a female partner at the same time if you both have symptoms.
BV in pregnancy
BV is common in pregnancy and usually harmless, but it slightly raises the risk of premature birth and late miscarriage, so it's treated rather than left. Tell your midwife or GP about any unusual discharge; lactic acid gels are safe to use while you wait to be seen, and metronidazole is safe in pregnancy if it's needed. Don't ignore it on the grounds that it doesn't itch.
When to see a GP or sexual health clinic
If this is your first episode and you're not sure it's BV, if you're pregnant, if there's pain, bleeding, fever or pain when you pee, if a week of gel hasn't worked, or if you've had a new partner and want a full STI screen, because BV and chlamydia can look identical and the only way to tell is a test. Our pharmacist can help you choose between the gels and tell you when to stop self-treating.
Frequently asked questions
Can BV go away on its own?
Sometimes, in about a third of cases, as the balance rights itself. But untreated BV lingers for weeks in most women and raises the risk of catching STIs, so treating it is worth the week.
Can men get BV?
No. Men have no vaginal flora to unbalance. They don't need treatment, and treating them doesn't prevent recurrence in their partner.
Can I have sex with BV?
You can, but it may make symptoms worse and, during treatment, can reduce how well the gel works. Use a condom or wait until the course is finished.
What does a BV test involve?
At a clinic, a swab from the vaginal wall examined under a microscope or sent to the lab. At home, a pH swab such as Canestest gives a strong hint in seconds but can't rule out other infections.