BV vs Thrush: How to Tell the Difference
Discharge, smell, itching and pH — the practical differences, and what to do when both are present.
Part of the Bacterial Vaginosis condition guide.
Key fact: Smell and itching separate the two more reliably than discharge alone — BV smells and rarely itches; thrush itches and rarely smells.
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Start a BV consultation →BV vs thrush: the comparison table
Bacterial vaginosis and vaginal thrush are the two most common causes of changed vaginal discharge, and they are routinely mistaken for one another. They are entirely different problems: BV is an imbalance in the bacteria that normally live in the vagina, while thrush is an overgrowth of Candida yeast. Because the treatments target different organisms, getting the distinction right is the difference between a resolved week and a wasted one.
The table below adds a third column for trichomoniasis. It is included because it is the condition most often missed when women are weighing up BV against thrush — it shares the odour and raised pH of BV, but it is a sexually transmitted infection needing different treatment and partner notification.
| Bacterial vaginosis | Thrush | Trichomoniasis | |
|---|---|---|---|
| What it is | Overgrowth of anaerobic bacteria, loss of lactobacilli | Overgrowth of Candida yeast | Infection with a parasite, Trichomonas vaginalis |
| Discharge consistency | Thin, watery, runny | Thick, often described as cottage cheese-like | Frothy or bubbly, often profuse |
| Discharge colour | Grey or off-white | White | Yellow or green |
| Smell | Fishy, stronger after sex and around periods | None, or a faint yeasty smell | Often unpleasant or musty |
| Itching | Usually absent | Prominent, often intense | Common |
| Soreness or stinging | Uncommon | Common, including stinging on passing urine | Common, often with pain on passing urine |
| Redness and swelling | Uncommon | Common around the vulva | Common |
| Vaginal pH | Raised, above 4.5 | Normal, 4.5 or below | Raised, above 4.5 |
| Sexually transmitted? | No — not classed as an STI | No | Yes |
| Treatment | Antibacterial — metronidazole or clindamycin | Antifungal — clotrimazole or fluconazole | Metronidazole, plus partner treatment |
| Available without prescription? | No — prescription only in the UK | Yes — sold in pharmacies | No — needs clinic testing first |
Why the third column matters. A pH self-test cannot separate BV from trichomoniasis, because both raise vaginal pH. If your discharge is frothy, yellow or green, do not treat it as BV — book a sexual health clinic appointment, because trichomoniasis requires partner notification that BV does not.
The two symptoms that separate them
Discharge appearance is the symptom most people focus on, and it is the least reliable one. Discharge varies with your cycle, and descriptions like “thick” and “thin” are subjective. Two symptoms discriminate much better.
Smell points to BV
A distinct fishy odour, particularly one that intensifies after unprotected sex, is characteristic of BV and is not a feature of thrush. It is caused by volatile amines released when vaginal pH rises.
Itching points to thrush
Persistent itching, soreness and stinging — especially with visible redness or swelling of the vulva — point to thrush. BV is often described as symptomatically “quiet” apart from the discharge and odour.
A useful way to hold it: BV is noticeable to your nose, thrush is noticeable to your skin. If you have odour without itching, treat that as BV until proven otherwise. If you have itching without odour, treat that as thrush.
Can you have both at once?
Yes, and it is more common than the neat table above suggests. Having BV and thrush together produces a mixed picture — itching and odour, or thick discharge with a fishy smell — which is exactly the presentation that leads people to keep buying the wrong product.
Two situations account for most co-occurrence:
- Thrush developing after BV treatment. Antibiotics suppress bacteria indiscriminately, which can let yeast overgrow. Thrush appearing in the days after a metronidazole course is common and expected.
- Genuine simultaneous infection. Both can simply be present at the same time, particularly in women who have had repeated episodes of either.
When both are present, both need treating — usually sequentially rather than at the same moment, and on a prescriber's advice. Treating only one leaves you with half your symptoms and the impression that the treatment failed.
If symptoms do not fit either pattern, stop self-treating. Repeatedly cycling through over-the-counter thrush products for symptoms that are not thrush is the single most common way a treatable problem persists for months. Two failed attempts is the point to get assessed rather than to try a third.
Checking at home before you treat
Vaginal pH is the most useful objective marker available outside a clinic, because it separates the two conditions cleanly: BV raises pH above 4.5, while thrush leaves it normal.
The Canestest self-test for vaginal infections is a pH-based swab you use at home, with a result in seconds. It will not name the organism and it does not replace clinical assessment, but for the specific question “should I be buying a thrush treatment or seeking BV treatment?” it is a sensible first step and usually cheaper than guessing wrong.
1
Check the pattern first
Odour without itching, or itching without odour, is often enough on its own. The mixed pictures are the ones worth testing.
2
Test if you are unsure
Use a pH self-test rather than buying a treatment speculatively. Avoid testing during a period or within 12 hours of sex, as both affect pH readings.
3
Match the treatment to the result
A raised pH points to BV, which needs prescription antibacterial treatment. A normal pH with itching points to thrush, treatable with a pharmacy antifungal.
4
Get assessed if it does not resolve
If a correctly matched treatment does not work, the diagnosis needs revisiting rather than repeating.
Why the treatments are not interchangeable
This is the practical consequence of the whole distinction. Antifungals and antibacterials act on completely different organisms, and neither has any effect on the other's target.
| Treatment | Works on | No effect on | Availability |
|---|---|---|---|
| Clotrimazole (Canesten) cream or pessary | Thrush | BV | Pharmacy |
| Fluconazole capsule | Thrush | BV | Pharmacy |
| Metronidazole tablets or Zidoval gel | BV | Thrush | Prescription only |
| Dalacin 2% (clindamycin) cream | BV | Thrush | Prescription only |
Because every BV treatment in the UK is prescription-only, there is no over-the-counter route to treating BV properly — which is part of why so many women end up with an antifungal by default. Our guide to BV treatment options compared sets out how the three prescription treatments differ, and BV gels compared covers the pharmacy products honestly, including what lactic acid gels can and cannot do.
When it is neither
Not all changed discharge is BV or thrush. Trichomoniasis produces frothy yellow-green discharge with an odour and can look very like BV. Chlamydia and gonorrhoea can change discharge, often with no other symptoms at all. These need testing, not self-treatment.
Seek medical assessment promptly if you have pelvic or lower abdominal pain, fever, pain during sex, bleeding between periods or after sex, or if you are pregnant with new discharge. None of these are features of uncomplicated BV or thrush. In an emergency, call 999.
It is also worth saying plainly that BV is not classed as a sexually transmitted infection in UK guidance, and women who have never had sex can develop it. Sexual activity does influence it, and evidence published in 2025 suggests exchange between regular partners contributes more to recurrence than was previously assumed — that is covered in our guide to recurrent BV.
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If your symptoms and pH point to BV, complete a short online consultation and our GPhC-registered pharmacist independent prescribers can supply treatment with discreet delivery.
Start a BV consultation →Frequently Asked Questions
How do I know if I have BV or thrush?
The most reliable everyday markers are smell and itching. BV typically causes a thin grey or white discharge with a fishy odour and little or no itching. Thrush typically causes thick white discharge with prominent itching and soreness, and little or no smell. If both are present, or neither pattern fits, testing is more reliable than guessing.
Can you have BV and thrush at the same time?
Yes. Having both together is well recognised and can produce a confusing mix of symptoms — itching alongside odour, for example. Each needs its own treatment, because an antibiotic will not clear thrush and an antifungal will not clear BV.
Does thrush smell fishy?
No. A fishy odour, particularly one that becomes stronger after sex, points towards BV rather than thrush. Thrush is usually odourless or has only a faint yeasty smell.
Will Canesten treat BV?
No. Canesten contains clotrimazole, an antifungal that works on Candida yeast. BV is a bacterial imbalance with no yeast involved, so antifungal treatments have no effect on it and BV needs an antibacterial such as metronidazole or clindamycin.
How accurate is a home test at telling BV from thrush?
Home tests such as Canestest measure vaginal pH, which is raised above 4.5 in BV and normal in thrush. That makes them useful for sorting symptoms into the right category before you buy a treatment. They do not diagnose specific organisms and do not exclude sexually transmitted infections.
Why does my discharge smell worse after sex?
Semen is alkaline, so it raises vaginal pH temporarily. In BV that triggers the release of the volatile amines responsible for the fishy odour, which is why the smell is often most noticeable after unprotected sex. This pattern is characteristic of BV rather than thrush.
How do I know if it is BV, thrush or something else?
Work through three features in order: odour, itching and discharge colour. Fishy odour without itching suggests BV. Itching without odour suggests thrush. Frothy yellow or green discharge suggests trichomoniasis, which needs clinic testing rather than either treatment. If none of the three patterns fits, get assessed rather than treating speculatively.
Completing the treatment
Once you know which condition you are dealing with, treatment is straightforward. Access Doctor supplies prescription BV treatment following an online consultation with a pharmacist independent prescriber, and stocks the Canestest self-test if you want to check first.
Self-test · Pharmacy
Canestest Self-Test
Checks vaginal pH at home to help distinguish BV from thrush before you treat.
View product →Bacterial vaginosis · Rx
Metronidazole 400mg Tablets
First-line oral antibiotic for BV, taken twice daily for five to seven days.
View product →Bacterial vaginosis · Rx
Zidoval Vaginal Gel
Metronidazole 0.75% gel applied nightly for five nights.
View product →Bacterial vaginosis · Rx
Dalacin 2% Cream
Clindamycin vaginal cream, a seven-night course with no alcohol restriction.
View product →References
- National Institute for Health and Care Excellence. Clinical Knowledge Summaries: Bacterial vaginosis. 2025. cks.nice.org.uk
- National Institute for Health and Care Excellence. Clinical Knowledge Summaries: Candida — female genital. cks.nice.org.uk
- NHS. Bacterial vaginosis. nhs.uk
- NHS. Thrush in men and women. nhs.uk
- British Association for Sexual Health and HIV. National guideline for the management of vaginal discharge. bashh.org
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.