Changes to vaginal discharge, smell or irritation can be difficult to interpret. Two common possibilities are bacterial vaginosis (BV) and vaginal thrush: BV develops when the usual balance of bacteria in the vagina changes, while thrush is caused by an overgrowth of Candida yeast. Although some symptoms can overlap, BV is more often linked with thin or watery discharge and a noticeable fishy smell, whereas thrush is more likely to cause itching, soreness and thick white discharge.
If you are trying to work out whether these changes could be BV or thrush, knowing the difference matters because the cause is not the same, and neither is the treatment. This guide explains the main differences in symptoms, causes, diagnosis and treatment, as well as why BV and thrush can come back and when it is sensible to seek medical advice.
However, symptoms alone cannot always tell you exactly what is happening.
Vaginal Infections at a Glance
| Symptom or feature | Bacterial vaginosis (BV) | Vaginal thrush |
| Main cause | Change in the natural balance of vaginal bacteria | Overgrowth of Candida yeast |
| Typical discharge | Thin, watery, greyish-white | Thick, white and sometimes lumpy |
| Smell | Often noticeably fishy | Usually little or no smell |
| Itching | Usually absent or mild | Common and can be intense |
| Soreness | Less typical | Common |
| Redness or irritation | Less common | More common |
| Pain during sex | Not usually a major symptom | Can occur |
| Pain or stinging when urinating | Less typical | Can occur due to irritation |
| STI? | Not classed as an STI | Not classed as an STI |
| Typical treatment type | Antibiotic treatment when required | Antifungal treatment |
These are typical patterns rather than a way of diagnosing yourself. The NHS recommends getting medical advice if your vaginal discharge changes in smell, colour or texture or you develop symptoms such as soreness, itching or pelvic pain.
What Is Bacterial Vaginosis?
Bacterial vaginosis, usually shortened to BV, happens when the normal balance of bacteria inside the vagina changes.
The vagina naturally contains different types of bacteria. BV is a common vaginal infection that develops when this balance is disrupted and bad bacteria become more dominant than good bacteria.
BV is common and is not classed as a sexually transmitted infection, although sexual activity can influence the vaginal environment and may trigger developing BV in some people. Risk factors include being sexually active and using an intrauterine device. The NHS also notes that around half of women with BV may have no symptoms at all.
When symptoms do occur, BV symptoms most often include:
- Thin or watery vaginal discharge
- Greyish-white discharge
- A strong or unusual fishy smell
- An odour that may become more noticeable after sex
- Increased vaginal discharge
Unlike thrush, BV does not usually cause significant itching or soreness.
For more detailed information specifically about the condition, its diagnosis and available care, see Broadgate GP’s bacterial vaginosis (BV) service. BV is a bacterial infection, and treatment commonly includes metronidazole.
What Is Vaginal Thrush?
Vaginal thrush is vaginal candidiasis, a yeast infection caused by candida fungus.
Candida can live naturally in the body without causing a problem. Thrush develops when conditions allow the yeast to multiply and produce symptoms of thrush.
Typical common symptoms of vaginal thrush include the main symptoms below:
- Itching around the vagina and vulva
- Irritation or redness
- Soreness
- Thick white vaginal discharge
- A cottage cheese like discharge
- Stinging when urinating
- A burning sensation
- Discomfort or soreness during sex
One particularly useful distinction between BV and thrush is smell. Vaginal thrush discharge does not usually have a strong smell, whereas a noticeable fishy odour is much more characteristic of BV, and BV is treated with antibiotics like metronidazole.
Broadgate GP has further information about thrush causes, symptoms, diagnosis and treatment.
What Is the Main Difference Between BV and Thrush?
The underlying cause is the biggest difference between thrush and BV.
BV is associated with an imbalance of vaginal bacteria.
Thrush is associated with an overgrowth of yeast or fungus.
That distinction matters because they are not treated in the same way. BV may require antibiotics, while vaginal thrush is generally treated using antifungal medication.
This is one reason repeatedly treating yourself for what you assume is thrush may not help: the right treatment depends on whether symptoms are due to thrush and bv, another vaginal infection, or other infections.
BV vs Thrush Discharge
Changes in vaginal discharge are one of the most useful clues when comparing the two conditions.
BV discharge
BV discharge is more likely to be:
- Thin
- Watery
- Greyish-white
- More noticeable than your usual discharge
BV is also more likely to cause unusual vaginal discharge, or unusual discharge with a strong fishy smell, which may become more noticeable after sex.
Thrush discharge
Thrush discharge is more likely to be:
- White
- Thick
- Lumpy
- Similar in appearance to cottage cheese
This is the classic cottage cheese like discharge seen with thrush. Discharge changes can occur with symptoms of thrush, but smell is usually minimal.
It does not usually have a strong or unpleasant smell.
Normal vaginal discharge can naturally change throughout the menstrual cycle, so a change in discharge does not automatically mean you have an infection. What matters is whether the colour, texture, amount or smell is unusual for you, particularly when other symptoms appear at the same time. The NHS provides further guidance on normal and abnormal vaginal discharge.
Does BV Itch Like Thrush?
Usually not.
Strong itching is much more characteristic of thrush than BV.
Thrush can make the skin around the vagina and vulva feel itchy, irritated, sore, inflamed, or cause a burning sensation, with external symptoms such as redness or soreness. Some people also experience stinging when passing urine because the surrounding skin has become irritated.
BV, by comparison, does not usually cause significant soreness or itching.
That does not mean itching automatically confirms thrush. Irritation can have several causes, including skin conditions, reactions to fragranced products, hormonal changes and some sexually transmitted infections.
If itching is severe, unusual or does not improve, it is sensible to have the cause assessed rather than repeatedly using over-the-counter treatments.
Fishy Smell – BV or Thrush?
A strong fishy vaginal smell is much more suggestive of BV than thrush.
BV can cause an unusual vaginal odour that may become particularly noticeable following sex.
Thrush, on the other hand, usually produces little or no vaginal smell. Its more prominent features tend to be itching, irritation and thick white discharge.
A new or unusual vaginal smell is not something you need to diagnose from smell alone. Other vaginal infections can also cause changes in odour and discharge.
Can You Have BV and Thrush at the Same Time?
Vaginal symptoms do not always fit neatly into a single category.
For example, someone experiencing a noticeable smell alongside significant itching may have symptoms that do not perfectly match the typical pattern for either BV or thrush.
There are also several other possible explanations for abnormal vaginal discharge, irritation or discomfort.
If symptoms appear mixed, persist despite treatment or repeatedly return, a clinician may need to assess what is causing them rather than assuming that the problem is BV or thrush.
Could BV or Thrush Actually Be an STI?
Neither BV nor thrush is classed as an STI, but some sexually transmitted infections can cause similar symptoms.
For example, vaginal discharge or genital discomfort can also occur with infections including:
- Chlamydia
- Gonorrhoea
- Trichomoniasis
- Genital herpes
The possibility of an STI may be particularly worth considering if your symptoms appeared following sex with a new partner, unprotected sex or another possible exposure.
Broadgate GP provides further information about confidential private sexual health services and STI testing.
Symptoms such as pelvic pain, bleeding between periods or after sex, sores or blisters, fever, or unusual green or yellow discharge should not simply be assumed to be BV or thrush.
Why Do I Keep Getting BV or Thrush?
Both conditions can come back, although the reasons are different.
BV can recur because the vaginal bacterial balance changes again. The NHS notes that recurrent BV is common and may return within a few months, and recurring bacterial vaginosis is worth a medical review if episodes happen often. Factors associated with BV can include changes in sexual partners, having an IUD and using perfumed products around the vagina.
Thrush may be more likely under circumstances including:
- Recent antibiotic use, which can trigger thrush by reducing protective bacteria
- Pregnancy
- Poorly controlled diabetes
- A weakened immune system
- Hormonal changes
- Irritation or damage to the skin
Recurring symptoms are particularly worth discussing with a healthcare professional because repeated episodes may need further assessment rather than simply repeating the same treatment.
Should You Treat BV or Thrush Yourself?
If you have previously been diagnosed with thrush and recognise exactly the same symptoms, a pharmacist may be able to advise about suitable treatment.
However, self-diagnosis becomes less reliable when:
- This is the first time you have experienced the symptoms
- Your symptoms are different from previous episodes
- Treatment has not worked
- Symptoms repeatedly return
- You have had sex with a new partner
- You are pregnant
- You have pelvic pain or unusual bleeding
- You are unsure whether you have BV, thrush or something else
Using a thrush treatment when the cause is actually BV will not address the bacterial imbalance, just as antifungal medication does not treat other vaginal infections, so it is important to get the right treatment.
What About BV or Thrush During Pregnancy?
Vaginal discharge naturally increases during pregnancy, but changes in smell, colour or consistency should still be discussed with your doctor or midwife.
The NHS advises speaking to a healthcare professional if you develop symptoms of BV while pregnant because BV can occasionally be associated with pregnancy complications.
Thrush is also common during pregnancy. If you think you have thrush while pregnant, speak to your GP, pharmacist or midwife before starting treatment, because not every thrush medicine is suitable during pregnancy.
When Should You Speak to a Doctor?
Consider seeking medical advice when vaginal symptoms are new, persistent, recurrent or difficult to identify.
In particular, get assessed if you have:
- A significant change in vaginal discharge
- A strong or unusual smell
- Persistent itching or soreness
- Pain when urinating or during sex
- Pelvic or lower abdominal pain
- Bleeding between periods or after sex
- Symptoms following a new sexual partner
- Symptoms that keep returning
- Symptoms that have not responded to treatment
- Concerns during pregnancy
You do not need to work out whether you have BV or thrush before speaking to a healthcare professional.
A consultation can look at the combination of symptoms and, where necessary, testing can help distinguish between BV, thrush, an STI or another cause of vaginal irritation. An at-home vaginal pH self-test kit may help suggest whether symptoms are more in keeping with BV or thrush, but it does not replace clinical assessment.
If symptoms are recurrent, hard to identify or occur during pregnancy, seek treatment promptly through your GP or a local sexual health clinic.
For broader women’s health concerns, Broadgate GP also provides a private women’s health clinic in London.
If your symptoms are new, unclear, recurrent or different from what you have experienced before, getting medical advice can help you understand what is actually causing them rather than treating the wrong condition.
Frequently Asked Questions
Is BV the same as thrush?
No. BV is associated with an imbalance of bacteria in the vagina, whereas thrush is caused by an overgrowth of Candida yeast.
How can I tell if I have BV or thrush?
BV more commonly causes thin greyish-white discharge and a fishy smell. The key difference between thrush and BV is that BV more often causes unusual discharge with a fishy smell, while thrush more often causes itching and thick white discharge. Symptoms alone cannot always confirm the cause.
Does BV cause itching?
BV does not usually cause significant itching or soreness. Strong itching is more commonly associated with thrush or another cause of vaginal irritation.
Does thrush cause a fishy smell?
Vaginal thrush does not usually produce a strong smell. A noticeably fishy vaginal smell is more characteristic of bacterial vaginosis.
Can BV be mistaken for thrush?
Yes. Both conditions can alter vaginal discharge, which means they can sometimes be confused. Looking at discharge texture, smell and itching can provide clues, but testing or a clinical assessment may be needed when symptoms are unclear.
Can you have BV and thrush symptoms together?
It is possible to have symptoms that do not clearly fit one condition. If you have both strong odour and significant itching, symptoms keep returning or treatment has only partly helped, seek medical advice rather than assuming the cause.
Are BV and thrush sexually transmitted?
Neither BV nor thrush is classed as an STI. However, sexual activity can influence BV, and thrush can sometimes be triggered by sex. If symptoms develop after a new sexual partner or possible STI exposure, sexual health testing may also be appropriate.
