Bacterial Vaginosis (BV): Symptoms, Fishy Odour, Causes and Treatment

Updated: August 2026

Bacterial vaginosis, commonly called BV, is a very common vaginal condition caused by an imbalance in the normal bacteria of the vagina.

A healthy vaginal environment usually contains large numbers of protective bacteria, particularly Lactobacillus species. In bacterial vaginosis, these protective bacteria decrease while other types of bacteria increase.

The result may be a thin vaginal discharge and a noticeable fishy vaginal odour, although many people with BV have no symptoms at all.

BV is treatable and curable, but it can return after successful treatment.

It is also important to understand what BV is not. Bacterial vaginosis is not the same as a vaginal yeast infection, and it is not classified simply as a conventional sexually transmitted infection such as gonorrhoea or chlamydia.

However, sexual activity is associated with BV, and having BV can increase the risk of acquiring some sexually transmitted infections.

What Is Bacterial Vaginosis?

The vagina naturally contains many different microorganisms.

Protective Lactobacillus bacteria help maintain an acidic vaginal environment that discourages excessive growth of other organisms.

In BV, the normal vaginal microbiome changes. Lactobacilli become less dominant and concentrations of other bacteria, including Gardnerella, Prevotella, Mobiluncus and other anaerobic bacteria, increase.

This change is known as vaginal dysbiosis.

BV is therefore better understood as an imbalance of the vaginal bacterial community rather than an infection caused by one single bacterium.

How Common Is Bacterial Vaginosis?

BV is one of the most common causes of abnormal vaginal discharge among women of reproductive age.

The World Health Organization reports that estimates from studies suggest BV affects approximately 23% to 29% of women of reproductive age globally, although prevalence varies substantially between countries and populations.

BV can occur without noticeable symptoms, which means some women may have the condition without knowing it.

What Are the Symptoms of Bacterial Vaginosis?

Some women with BV have no symptoms.

When symptoms occur, the most characteristic ones include:

• Thin or unusual vaginal discharge
• A strong fishy or musty vaginal odour
• Vaginal irritation
• Itching around the vagina
• Burning during urination

The discharge is often described as thin, homogeneous and greyish-white, although appearance can vary.

The fishy smell may sometimes become more noticeable after sex or during menstruation.

Does a Fishy Vaginal Smell Always Mean BV?

No.

A characteristic fishy odour is strongly associated with BV, but vaginal odour alone cannot confirm the diagnosis.

Other vaginal and sexually transmitted infections can cause discharge, irritation or unusual odour.

For example, trichomoniasis can cause vaginal discharge and may sometimes produce an unpleasant smell.

This is why repeatedly treating yourself for BV based only on smell or discharge can lead to the wrong treatment.

Persistent or recurrent vaginal symptoms deserve proper assessment.

Is Bacterial Vaginosis an STI?

BV has a complicated relationship with sexual activity.

It is not generally classified as a conventional STI caused by a single sexually transmitted pathogen.

Researchers still do not completely understand exactly how the microbial changes that produce BV begin.

However, BV is associated with sexual behaviours and is more common among sexually active women.

Factors associated with BV include:

• Having a new sexual partner
• Having multiple sexual partners
• Having female sexual partners
• Not using condoms
• Vaginal douching

BV can occur without sexual activity, although it is uncommon among women who have never been sexually active.

Sex therefore matters in understanding BV, but describing BV simply as an STI is misleading.

Can You Get BV From a Toilet Seat, Bed or Swimming Pool?

There is no evidence that BV is acquired from ordinary contact with:

• Toilet seats
• Bedding
• Swimming pools

BV results from changes in the vaginal bacterial environment rather than the kind of casual transmission associated with sharing household surfaces.

Poor personal hygiene should therefore not automatically be blamed when someone develops BV.

What Causes Bacterial Vaginosis?

The exact biological event that triggers BV is still not completely understood.

What is known is that the normal vaginal microbiome changes, allowing BV-associated bacteria to become more dominant.

Several factors are associated with an increased likelihood of developing BV.

These include:

• Vaginal douching
• Having a new sexual partner
• Having multiple sexual partners
• Having female sexual partners
• Inconsistent or absent condom use
• Certain intravaginal practices, including inserting herbs or other products into the vagina
• Menstruation, during which BV prevalence may increase
• Use of a copper-containing intrauterine device in some women

These are risk factors and associations, not proof that any single behaviour directly caused an individual woman's BV.

Does an IUD Cause BV?

This needs some nuance.

Evidence suggests BV prevalence may be higher among women using copper-containing intrauterine devices.

That does not mean every woman using a copper IUD will develop BV or that an IUD must automatically be removed when BV occurs.

Hormonal contraception has not been shown to increase BV risk and may potentially have a protective effect.

Women experiencing recurrent symptoms while using contraception should discuss their individual situation with a healthcare professional rather than stopping contraception on their own.

Is BV the Same as a Yeast Infection?

No.

They are different conditions.

BV involves a disruption of the normal vaginal bacterial community.

A vaginal yeast infection, also called vulvovaginal candidiasis, is usually caused by excessive growth of Candida yeast.

BV is particularly associated with thin discharge and fishy odour, while vaginal candidiasis more commonly causes intense itching, irritation and thick discharge.

However, symptoms can overlap.

A woman can also have more than one vaginal condition at the same time.

This is why vaginal discharge should not always be self-diagnosed as either BV or a yeast infection.

How Is Bacterial Vaginosis Diagnosed?

A healthcare professional may ask about symptoms, sexual history, menstrual history, vaginal hygiene practices and medicines or products being used inside the vagina.

Examination and testing of vaginal fluid can then help establish the diagnosis.

Several approaches are available.

Amsel Criteria

One established clinical approach uses the Amsel criteria.

The four criteria are:

1. Thin, homogeneous vaginal discharge
2. Vaginal fluid pH greater than 4.5
3. Clue cells seen during microscopic examination
4. A characteristic fishy odour during the amine or "whiff" test

Generally, the presence of at least three of the four criteria supports a clinical diagnosis of BV.

Vaginal Gram Stain

A vaginal fluid sample can also be examined using Gram staining.

The Nugent scoring system evaluates the relative amounts and types of bacteria visible under the microscope.

Gram staining with Nugent scoring is an important laboratory method for diagnosing BV.

Other Tests

Depending on the healthcare setting, molecular or point-of-care tests may also be available.

A vaginal pH above 4.5 can support a diagnosis but does not diagnose BV by itself.

Why Self-Diagnosing Vaginal Discharge Can Be Difficult

Vaginal discharge, itching, irritation and odour can occur with several conditions.

These include:

• Bacterial vaginosis
• Vulvovaginal candidiasis
• Trichomoniasis
• Cervicitis
• Some sexually transmitted infections
• Non-infectious irritation or inflammation

Medical history alone may not be sufficient to determine the cause accurately.

This is particularly important when symptoms keep returning despite treatment.

How Is Bacterial Vaginosis Treated?

BV is treatable and curable.

Antibiotics are the main evidence-based treatment for symptomatic bacterial vaginosis.

The World Health Organization recommends metronidazole as a principal treatment option, with other antibiotic regimens available depending on individual circumstances, pregnancy, availability, tolerability and clinical judgement.

Treatment options may include:

• Metronidazole taken orally
• Metronidazole vaginal gel
• Clindamycin
• Tinidazole in appropriate circumstances
• Secnidazole in appropriate circumstances

The exact medicine, dose and duration should follow appropriate clinical guidance and the healthcare professional's assessment.

People should complete prescribed treatment even when symptoms improve before the medicine is finished.

Should Every Woman With BV Be Treated?

Treatment is particularly recommended for women who have symptoms.

Pregnancy requires additional consideration because symptomatic BV during pregnancy has been associated with adverse pregnancy outcomes.

Anyone who is pregnant and develops unusual vaginal discharge, odour, irritation or other concerning symptoms should seek appropriate healthcare rather than relying on self-treatment.

Can BV Go Away Without Treatment?

BV can sometimes resolve without treatment.

However, that does not mean persistent symptoms should simply be ignored.

Treatment can relieve symptoms, and BV is associated with increased risks of certain reproductive and sexual-health complications.

Women with persistent, troublesome, recurrent or pregnancy-associated symptoms should seek medical assessment.

Can Bacterial Vaginosis Come Back?

Yes.

Recurrence is common, even after apparently successful treatment.

A recurrence does not necessarily mean that someone failed to take treatment correctly.

BV involves a complex vaginal microbial environment, and the reasons some women repeatedly develop BV are still being investigated.

Women whose symptoms return should seek medical advice rather than repeatedly using leftover antibiotics or treating themselves without confirming the diagnosis.

Recurrent symptoms may also turn out to have another cause.

Should My Sexual Partner Be Treated?

This depends on the circumstances and evolving clinical evidence.

Historically, routine treatment of male partners has not been recommended because earlier studies did not consistently show that it prevented BV recurrence.

BV can also occur among women who have sex with women, and BV-associated bacterial communities may be shared between female partners.

People experiencing recurrent BV should discuss their sexual history and recurrence pattern with a healthcare professional so that management can reflect current clinical guidance and their individual circumstances.

Can BV Increase the Risk of HIV or Other STIs?

Yes.

BV is associated with an increased risk of acquiring several sexually transmitted infections.

These include infections such as:

• HIV
• Chlamydia
• Gonorrhoea
• Trichomoniasis
• Genital herpes
• HPV

This does not mean that having BV means someone has an STI.

It means that the changes associated with BV can increase susceptibility to certain infections when exposure occurs.

People with BV who may have been exposed to an STI should discuss appropriate testing with a healthcare professional.

Bacterial Vaginosis During Pregnancy

BV deserves particular attention during pregnancy.

Symptomatic BV has been associated with adverse pregnancy outcomes, including preterm birth and other pregnancy complications.

Pregnant women with symptoms should therefore seek appropriate medical assessment.

Antibiotic options and treatment decisions during pregnancy should be selected by a qualified healthcare professional.

Pregnancy is not a good time to experiment with unproven vaginal remedies.

Can Untreated BV Cause Pelvic Inflammatory Disease?

BV is associated with an increased risk of some reproductive-tract complications and sexually transmitted infections that can contribute to pelvic inflammatory disease.

PID can affect reproductive health and fertility.

However, BV should not be described as automatically progressing to PID in every untreated woman.

Risk depends on several factors, including exposure to other infections.

Are Home Remedies Effective for BV?

Be cautious with online claims about home treatment.

Products frequently promoted for BV include:

• Apple cider vinegar
• Coconut oil
• Yogurt inserted into the vagina
• Herbal preparations
• Antiseptic washes

These should not replace evidence-based diagnosis and antibiotic treatment when treatment is indicated.

Putting acidic, scented, herbal or other unapproved substances inside the vagina can cause irritation and may further disturb the vaginal environment.

What About Probiotics?

Researchers continue to study whether certain probiotics can help restore a healthier vaginal microbiome or reduce BV recurrence.

However, probiotic products vary considerably in their bacterial strains, doses and quality.

They should not be presented as a proven substitute for recommended antibiotic treatment of symptomatic BV.

Anyone considering probiotics for recurrent BV should discuss this with a healthcare professional.

Should You Douche to Remove the Fishy Smell?

No.

Douching is associated with BV and may increase the likelihood of recurrence.

The vagina has its own microbial environment and does not need internal washing with soap, antiseptics, perfumes or other cleansing products.

Washing the external genital area gently is different from putting cleansing products inside the vagina.

Using douches to temporarily hide an odour can make the underlying problem more difficult rather than treating its cause.

How Can You Reduce the Risk of BV?

Because the exact cause of BV is not completely understood, no prevention method guarantees that BV will never occur.

Measures that may help reduce risk include:

• Avoid vaginal douching
• Avoid inserting unnecessary herbs, antiseptics or cleansing products into the vagina
• Use condoms consistently
• Consider the association between new or multiple sexual partners and BV
• Seek medical assessment when symptoms persist or repeatedly return
• Complete prescribed treatment
• Avoid repeatedly self-treating vaginal symptoms without confirming their cause

When Should You See a Healthcare Professional?

Consider medical assessment if you develop:

• Persistent fishy vaginal odour
• New or unusual vaginal discharge
• Burning during urination
• Persistent vaginal irritation or itching
• Symptoms that return after treatment
• Vaginal symptoms during pregnancy
• Pelvic or lower abdominal pain
• Fever
• Bleeding that is unusual for you
• Possible exposure to a sexually transmitted infection

Pelvic pain, fever or significant illness deserves particular attention because these symptoms may suggest something other than uncomplicated BV.

Common Myths About Bacterial Vaginosis

Myth: BV means you have poor hygiene.

False. BV involves changes in the vaginal microbiome. Excessive vaginal cleansing and douching may actually increase the risk.

Myth: BV is simply an STI.

Not exactly. BV is associated with sexual activity and sexual behaviours, but it is not regarded in the same way as a conventional STI caused by one specific sexually transmitted pathogen.

Myth: A fishy smell definitely means BV.

Not always. BV is a common cause, but other conditions can produce abnormal discharge or odour.

Myth: BV and vaginal yeast infection are the same thing.

False. BV involves bacterial dysbiosis, while vaginal candidiasis involves excessive growth of Candida yeast.

Myth: Apple cider vinegar can cure BV.

There is insufficient evidence to recommend apple cider vinegar as a treatment for BV, and putting irritating substances inside the vagina may cause harm.

Myth: BV can never return after antibiotics.

False. Recurrence is common and may require further clinical assessment.

Frequently Asked Questions

What does BV discharge look like?

BV commonly produces a thin, homogeneous vaginal discharge that may appear white or greyish.

What does BV smell like?

A strong fishy vaginal odour is characteristic of BV, although not every woman with BV notices an odour.

Can you have BV without symptoms?

Yes. Many women with BV have no noticeable symptoms.

Is BV caused by having sex?

The relationship is more complicated. Sexual activity, new partners, multiple partners and lack of condom use are associated with BV, but researchers have not identified one single sexually transmitted organism as its cause.

Can a virgin get bacterial vaginosis?

BV can occur in someone who has never had sex, although it is uncommon among women who have never been sexually active.

Can BV return after treatment?

Yes. Recurrence is common.

Can BV affect pregnancy?

Yes. Symptomatic BV during pregnancy has been associated with adverse pregnancy outcomes, including preterm birth.

Is BV the same as candidiasis?

No. BV is associated with changes in vaginal bacteria, while candidiasis is caused by excessive growth of Candida yeast.

Key Takeaways

Bacterial vaginosis is a common condition caused by an imbalance in the vaginal microbiome.

A thin discharge and fishy vaginal odour are characteristic symptoms, although many women have no symptoms.

BV is associated with sexual activity but should not simply be described as a conventional sexually transmitted infection.

It can increase susceptibility to HIV and several other STIs and is associated with pregnancy complications.

BV is treatable with appropriate antibiotics, but recurrence is common.

Douching and unproven vaginal home remedies should be avoided.

And because BV, candidiasis, trichomoniasis and other conditions can produce overlapping symptoms, persistent or recurrent vaginal discharge should be properly assessed rather than repeatedly self-treated.

Continue Reading on AnjKreb

Vaginal Yeast Infection: Symptoms, Causes and Treatment

Genital Warts and HPV: Symptoms, Treatment, Transmission and Cancer Risk

Cervical Cancer: Causes, Symptoms, Screening, Treatment and Prevention

References and Further Reading

World Health Organization. Bacterial vaginosis. Updated 21 November 2025.

World Health Organization. Recommendations for the treatment of Trichomonas vaginalis, Mycoplasma genitalium, Candida albicans, bacterial vaginosis and human papillomavirus (anogenital warts). 16 July 2024.

Centers for Disease Control and Prevention. Bacterial Vaginosis: STI Treatment Guidelines.

Centers for Disease Control and Prevention. About Bacterial Vaginosis (BV).

About the Author

Adeyinka Joseph Alonge is a public health professional, researcher and writer with interests spanning health, science, technology, personal development and practical knowledge for everyday life.