Unusual vaginal discharge is one of the most common reasons people reach for a pharmacy shelf, and thrush treatments are usually the first thing people try because they're so widely advertised and available without a prescription. The trouble is that bacterial vaginosis (BV) is actually the more common cause of discharge in women of reproductive age, and an antifungal thrush treatment won't do anything for it.
BV and thrush can look similar at first glance: both can change the colour, texture or amount of discharge, and both are common, not dangerous for most people, and not classed as sexually transmitted infections. But the underlying cause, the exact symptoms, and the treatment are all different, which is why telling them apart matters before you start treating either one.
BV and thrush at a glance
Bacterial vaginosis happens when the normal balance of bacteria in the vagina shifts: the protective lactobacilli that usually dominate fall in number, and a mix of other bacteria grows in their place. It isn't an infection you catch from a single source, and it isn't caused by poor hygiene.
Thrush, by contrast, is caused by an overgrowth of Candida, a yeast that lives harmlessly in the vagina for most people most of the time. When something disrupts the balance, for example a course of antibiotics, pregnancy, or a dip in immunity, Candida can multiply and cause symptoms.
Both are extremely common. Most women will have at least one episode of BV and at least one episode of thrush at some point. Neither is an STI, though sexual activity is one of several factors linked with a higher chance of BV specifically.
A lot of the confusion comes down to how visible each condition is on the pharmacy shelf. Thrush treatments are widely advertised and sit in plain view, so when something feels "off" down there, reaching for a thrush cream or pessary is often the instinctive first move. BV treatments, by contrast, are prescription-only in the UK, so people rarely think to ask for them unless they already know BV is a possibility. This mismatch is a major reason BV so often gets self-treated with the wrong product.
Symptoms: how discharge, smell and itching differ
The clearest clues are in the discharge itself and whether there's any itching:
- BV discharge: thin and watery, grey or off-white, with a distinctive fishy smell that's often more noticeable after sex or during a period. Itching and soreness are uncommon.
- Thrush discharge: thick and white, often described as looking like cottage cheese, usually with little to no smell. Itching, soreness and stinging, especially when you pee or during sex, are typical.
Around half of people with BV have no symptoms at all and only find out incidentally, for example during a routine screening appointment. Thrush is much more reliably symptomatic: most people notice itching or discomfort quite quickly.
If you're trying to work it out at home, the presence or absence of itching is usually the single most useful clue, followed by whether there's a noticeable smell. But symptoms can overlap, vary between episodes, or be mild enough to be ambiguous, which is exactly why a quick pharmacist check is often worth it before choosing a treatment.
What causes each one
Several everyday factors are linked with a higher chance of BV developing:
- Vaginal douching or internal washing, which removes protective bacteria along with everything else.
- Scented soaps, shower gels, bubble baths and vaginal deodorants, which disturb the natural pH.
- New or multiple sexual partners.
- Having a copper coil (IUD), which some studies link with a modestly higher BV risk.
- Smoking.
Thrush, meanwhile, tends to follow a different set of triggers:
- A recent course of antibiotics, which can disturb the normal bacterial balance that usually keeps Candida in check.
- Pregnancy, due to hormonal changes.
- Poorly controlled diabetes, since higher sugar levels can encourage yeast growth.
- A weakened immune system.
- Tight, non-breathable underwear or clothing, which creates a warm, damp environment Candida favours.
Neither condition is caused by not washing enough, and washing more, particularly internally, usually makes things worse rather than better for both. The vagina is self-cleaning; water alone on the outside is all that's needed day to day.
How they're diagnosed
A pharmacist, GP or sexual health clinic can usually tell the difference from your symptoms and a brief examination, sometimes supported by checking the vaginal pH or looking at a sample under a microscope. Because BV, thrush and some STIs can present similarly, testing helps confirm you're treating the right thing rather than guessing.
Home vaginal pH self-test kits are available and can offer a useful first clue, since BV typically raises vaginal pH while thrush doesn't, but they're not a substitute for a proper clinical assessment, particularly if this is your first episode or your symptoms don't fit the usual pattern.
It's also worth knowing that some STIs, including trichomoniasis, can cause discharge that looks similar to BV at first glance, with a change in colour, smell or consistency. This is another reason a confirmed diagnosis matters rather than assuming it must be one of the two most common causes: if symptoms don't settle with standard BV or thrush treatment, a wider STI screen is a sensible next step rather than trying a third over-the-counter product.
Treatment differences
UK first-line treatment for BV is a course of metronidazole tablets, usually taken twice daily for five to seven days. Topical alternatives work just as well for many people: metronidazole vaginal gel applied once daily at night for five nights, or clindamycin vaginal cream applied once daily at night for seven nights.
Thrush is treated differently: a single oral dose of fluconazole clears most cases within a few days, and a clotrimazole pessary or cream is a suitable alternative for people who can't take fluconazole, including during pregnancy, when oral antifungals aren't usually recommended.
Using the wrong product is a common and avoidable setback. An antifungal cream won't touch the bacterial imbalance behind BV, and an antibiotic won't help genuine thrush, so a mismatched self-treatment often just means paying twice and staying uncomfortable for longer. If symptoms don't settle within a few days of treatment, or if you're not confident which condition you're dealing with, it's worth getting this confirmed rather than switching products and trying again.
Can you have both at once, and when to see a doctor
It's entirely possible to have BV and thrush at the same time, which can make the overall picture confusing: you might have the smell typical of BV alongside the itching typical of thrush. This is one of the more common reasons a single self-bought treatment doesn't fully resolve symptoms, and it's a good reason to get a proper assessment rather than keep guessing.
See a pharmacist, GP or sexual health clinic if:
- This is your first time with these symptoms, so the cause can be confirmed.
- You're pregnant.
- Symptoms haven't improved within a week of completing treatment.
- Either condition keeps recurring: three or more episodes in a year is generally considered worth investigating further.
- You have pelvic pain, fever, or bleeding between periods or after sex, which point to something other than straightforward BV or thrush and need assessment.
These red flags matter because, left untreated, some vaginal and pelvic infections can contribute to more serious problems. BV and thrush are not dangerous for most people, but symptoms that don't fit the usual pattern, or that keep coming back, are worth a proper look rather than repeat self-treatment.
A Farmeci consultation can help confirm which condition is the likely cause of your symptoms, arrange the right treatment, and talk through a longer-term plan if either keeps recurring for you; your clinician will always tailor this to your individual circumstances.