Thrush and bacterial vaginosis, usually called BV, are two of the most common causes of vaginal symptoms in the UK. They are often confused with each other, and that confusion matters because the best treatment for one is not the best treatment for the other. A lot of women assume that any discharge, odour or irritation must be thrush, buy a treatment from the pharmacy, and then wonder why nothing really improves. Others worry they may have an STI when the cause is actually something much more common and usually straightforward to treat.
The simplest way to think about it is this: thrush usually causes itching and soreness, while BV is more often linked to a fishy smell and thin discharge. That is not a perfect rule, but it is a very useful starting point.
This guide explains what thrush and BV are, how they differ, what symptoms are more typical of each one, what to avoid, what treatment usually works best, and when it is time to stop guessing and get checked properly.
If you want the wider picture first, see our guides to Vaginal Discharge: What’s Normal, What’s Not and When to Get Checked, Women’s Health: Symptoms, Common Conditions, Tests and Treatment Options in the UK, and Menopause: Symptoms, HRT and Treatment in the UK if dryness or irritation is happening later in life.
What is thrush?
Thrush is a yeast infection, usually caused by an overgrowth of Candida. Small amounts of this yeast can live in the body without causing problems, but when the balance changes, symptoms can appear.
Thrush is very common. It can happen after antibiotics, during pregnancy, with diabetes, after irritation from products, or sometimes for no obvious reason at all. It is not usually classed as a sexually transmitted infection, although sex can sometimes make symptoms feel worse because irritated tissue becomes more noticeable.
What is BV?
BV, or bacterial vaginosis, happens when the usual balance of bacteria in the vagina changes. It is one of the most common causes of unusual vaginal discharge in women of childbearing age. BV is not usually classed as an STI, but it can raise the risk of getting one, which is one reason recurrent or unclear symptoms should not just be ignored.
Unlike thrush, BV often does not cause much itching or soreness. That difference is one of the most helpful clues.
The quickest way to tell them apart
If you only remember one section from this article, make it this one.
- Thrush is more likely to cause itching, irritation, soreness and a thick white discharge that usually does not smell strongly.
- BV is more likely to cause a thin greyish-white discharge with a strong fishy smell, especially after sex, and usually causes little or no itching.
That is the classic pattern. Real life is not always textbook-perfect, but this comparison is often enough to help someone realise why the thrush treatment they keep buying is probably not the right answer.
Common thrush symptoms
Thrush often causes a very uncomfortable, irritated feeling. Common symptoms include:
- itching around the vulva and vagina
- soreness or burning
- stinging during sex
- stinging when you pee
- white vaginal discharge, often thicker or lumpy
- little or no strong smell
Some women say the main issue is not the discharge at all, but the irritation. They feel sore, rubbed raw, swollen, or unable to stop thinking about the itching. That pattern points much more toward thrush than BV.
Common BV symptoms
BV often feels different. The most typical symptoms are:
- thin, watery or smooth discharge
- greyish-white discharge
- a noticeable fishy smell
- odour that may be stronger after sex
- often no itching or soreness
Some women with BV have no symptoms at all and only notice a change in smell or discharge. Others become very distressed by the odour, especially because it can be mistaken for poor hygiene. It is not a hygiene problem. It is a change in vaginal bacteria.
What if you are not sure which one it is?
This is extremely common. Symptoms can overlap, especially if irritation has led to over-washing, repeated treatment, or anxiety about what is happening. The main problem usually comes when people keep treating “probably thrush” over and over, even though the pattern actually sounds more like BV, irritation, an STI, or something else entirely.
As a rough rule:
- Mainly itchy and sore? Think more about thrush.
- Mainly smelly with thin discharge? Think more about BV.
- Green, yellow or frothy discharge? Think about something else, including possible STI.
- Pelvic pain or bleeding after sex? Do not self-diagnose. Get checked.
What causes thrush to flare up?
Thrush often appears when the natural balance in the vagina is disturbed. Common triggers include:
- recent antibiotics
- pregnancy
- diabetes, especially if poorly controlled
- tight, sweaty clothing for long periods
- irritating soaps or intimate products
- a tendency to recurrent thrush
It is also common for women to think sex “caused” thrush when what actually happened is that friction made already irritated tissue more obvious.
What causes BV to happen?
BV happens when the normal bacterial balance shifts. It is not usually caused by being unclean, and it is not simply something people “catch” in the same way as a typical STI. It can happen after sex, after using strongly perfumed products, or with other changes that affect the vaginal environment, but sometimes there is no clear trigger.
One of the most unhelpful things women hear is that smell means they are doing something wrong. Usually they are not. In fact, trying to wash more aggressively often makes things worse.
Can you have both at once?
Yes, it is possible to have more than one issue going on, which is one reason recurring symptoms can get confusing. A woman may treat thrush, improve briefly, then still notice discharge or odour because BV or another cause was also present. That is why repeated symptoms deserve proper testing rather than endless trial and error.
What treatment works best for thrush?
Thrush is often treated with antifungal medication. That may be a cream, pessary inserted into the vagina, or an oral antifungal tablet, depending on what is suitable for you and what the pharmacist or doctor advises.
For many women, pharmacy treatment works well if the symptoms are typical and they have had thrush before. But if symptoms are different from usual, not improving, or coming back repeatedly, it is better to get checked rather than just trying the same thing again.
What treatment works best for BV?
BV is usually treated with antibiotics, commonly through a GP or sexual health clinic. Because BV is caused by a bacterial imbalance rather than yeast, antifungal thrush treatment will not fix it. That is the key difference.
This is why a woman may say, “I used thrush treatment twice and it still smells the same.” In that situation, BV becomes much more likely.
Can you buy treatment over the counter?
You can often buy thrush treatment from a pharmacy if the pattern is typical. BV is different. If symptoms suggest BV, especially a strong fishy smell with thin discharge, you usually need proper assessment and treatment advice rather than just picking up a standard thrush product.
Pharmacists can be very helpful here. Even when they cannot solve everything directly, they are often the fastest way to hear, “This does not sound like thrush — you should get checked.”
When should you stop guessing and get checked?
You should get checked if:
- this is the first time you have had symptoms
- you are not sure whether it is thrush or BV
- symptoms are different from usual
- treatment has not worked
- symptoms keep coming back
- you have pelvic pain
- you have bleeding after sex or between periods
- you have green, yellow or frothy discharge
- you may have been exposed to an STI
- you are pregnant
A GP or sexual health clinic is the right next step in those situations. Sexual health clinics are especially useful when STI testing might be relevant, and many can see people quickly.
What tests might be done?
If the diagnosis is unclear, you may be offered a swab or other tests to check for thrush, BV or STIs. Depending on symptoms, a clinician may also ask about bleeding, pelvic pain, urinary symptoms, recent sex, antibiotics, pregnancy and menopause status.
These questions are not there to embarrass you. They are there because discharge problems have more than one cause, and the right treatment depends on getting the cause right.
What to avoid
There are a few common mistakes that make both thrush and BV harder to sort out:
- repeatedly treating every symptom as thrush
- using scented soaps, vaginal washes or deodorising products
- douching or washing inside the vagina
- assuming smell always means poor hygiene
- ignoring symptoms after a new sexual partner
- putting off testing because the symptoms feel embarrassing
The vagina is self-cleaning. In most cases, gentle external washing with water or a non-irritating product is enough. More cleaning is not better cleaning here.
What if symptoms keep coming back?
Recurring symptoms are a sign to get a proper review rather than staying in self-treatment mode. Recurrent thrush may need confirmation, a longer treatment plan, or investigation for triggers such as diabetes or antibiotic use. Recurrent BV may need reassessment, advice about recurrence, and sometimes testing to rule out other causes. Symptoms that keep returning can also turn out not to be either thrush or BV at all.
If symptoms are recurring later in life, especially with dryness or pain during sex, menopause-related vaginal changes should also be considered. That is one reason not to assume every irritation problem is infection.
External resources
For reliable UK information, see the NHS guide to thrush, the NHS guide to bacterial vaginosis, and the NHS page on vaginal discharge and infection signs.
Key takeaway
Thrush and BV are both common, but they usually behave differently. Thrush is more about itching, soreness and thick white discharge without a strong smell. BV is more about thin discharge with a strong fishy smell and usually little or no itching. The best treatment depends on getting that distinction right.
If symptoms are new, unclear, recurring, linked to pelvic pain or bleeding, or not improving with treatment, it is time to stop guessing and get checked properly. That often saves a lot of discomfort and a lot of money spent on the wrong treatment.
