BV smell: what causes that fishy odor and what actually clears it

A BV smell usually comes from an imbalance in vaginal bacteria. When protective Lactobacillus bacteria decrease and the vaginal pH rises, other bacteria can multiply and produce volatile amines with a distinct fishy odor.

It has nothing to do with being dirty or not washing enough. In fact, douching, scented washes, and trying to scrub the smell away can make the imbalance worse.

The treatment that actually clears symptomatic BV is an appropriate antibiotic prescribed by a clinician. The odor often starts improving within a few days, but if it persists or keeps coming back, the next step is to make sure the diagnosis is correct and look at why the BV is recurring.

TL;DR: Key takeaways

• The fishy BV smell comes from volatile amines produced by bacteria when the vaginal microbiome becomes imbalanced.
• BV is not a hygiene problem. Washing more or douching does not clear it and can make recurrence more likely.
• Sex can make the odor more noticeable because semen is alkaline and temporarily raises vaginal pH.
• A fishy odor alone does not prove you have BV. Discharge, pH, microscopy, and other testing can help distinguish BV from yeast, trichomoniasis, and other causes.
• Over-the-counter yeast treatments do not treat BV.
• Antibiotics are the evidence-based treatment for symptomatic BV. If symptoms persist or return after treatment, you may need another evaluation rather than simply repeating the same treatment on your own.

Not sure if your symptoms sound like BV, a yeast infection, or something else? Try August AI’s free Symptom Checker to get a quick idea of what may be going on and how soon you should seek care.

If your symptoms sound like BV, August’s $39 online urgent care visit connects you with a US licensed clinician who can review your symptoms and medical history and decide whether treatment is appropriate. Keep in mind that telehealth cannot perform a pelvic exam or collect a vaginal sample, so you may still need in-person testing if your symptoms are unclear, severe, or keep coming back.

The BV smell is a chemical signal, not a cleanliness problem

The characteristic BV smell comes from compounds called volatile amines. Bacteria associated with BV can produce compounds such as trimethylamine, putrescine, and cadaverine as they break down proteins and other substances in the vaginal environment.

That is what gives BV its familiar fishy odor.

Normally, Lactobacillus bacteria help keep the vagina acidic. When those bacteria decrease, vaginal pH can rise above about 4.5, creating an environment where BV-associated bacteria can thrive.

The result is often a combination of:

• Thin, homogeneous gray or white discharge
• A noticeable fishy odor
• A stronger smell after sex or around menstruation
• Little or no itching

That last point can be useful when comparing BV with other vaginal conditions. Yeast infections more commonly cause intense itching and thick, clumpy discharge, while BV often causes odor and discharge without significant irritation.

And one misconception is worth clearing up: BV is not caused by poor hygiene. A strong odor does not mean you need to wash more. The problem is the bacterial balance inside the vagina, not dirt on the outside.

Douching and scented washes can make a BV smell worse

If you notice a strong vaginal odor, the instinct may be to wash more often, use a scented wash, or douche.

That can backfire.

Douching can disrupt the normal vaginal microbiome and is associated with a higher risk of BV recurrence. The CDC specifically advises against douching because it does not treat BV and may increase the risk of relapse.

The same applies to scented sprays, deodorizing products, and products marketed as "feminine freshness." They may temporarily cover the smell, but they do not remove the bacteria producing it.

For everyday care, keep it simple:

• Wash the outside of the vulva with water.
• Avoid putting soap, washes, or sprays inside the vagina.
• Skip douching.
• Avoid vaginal steaming and other products marketed as ways to "clean" the vagina.

You do not need to make the vagina smell like perfume. A healthy vagina has a natural smell, and that smell can change throughout the menstrual cycle.

A persistent fishy odor is different because it can be a sign that something has changed in the vaginal microbiome.

Why does the BV smell get stronger after sex?

Many people notice the smell most clearly after sex.

There is a straightforward reason for that. Semen is relatively alkaline, while a healthy vaginal environment is acidic. When semen enters the vagina, it temporarily raises the vaginal pH.

That change can make the volatile amines associated with BV more noticeable. This is also the basic principle behind the traditional "whiff test" used when evaluating BV: when a clinician adds potassium hydroxide to vaginal fluid, volatile amines can produce a characteristic fishy odor.

So noticing a stronger smell after sex does not necessarily mean you developed a new infection that night.

It can simply make an existing imbalance much easier to notice.

A temporary change in vaginal smell after sex can be normal. The bigger clue is what happens repeatedly.

If you consistently get a strong fishy odor after sex, especially with thin gray-white discharge, BV becomes more likely and is worth getting checked.

A fishy odor alone does not diagnose BV

A vaginal fishy smell is a classic BV symptom, but smell alone is not enough to diagnose it.

Clinicians can diagnose BV using Amsel criteria or laboratory testing. Under the Amsel approach, at least three of four findings support a diagnosis:

• Thin, homogeneous vaginal discharge
• Vaginal pH above 4.5
• A positive amine or "whiff" test
• Clue cells seen on microscopy

A Nugent score from a vaginal Gram stain is another established diagnostic method.

That matters because several vaginal conditions can cause odor or unusual discharge.

What different symptoms can suggest

Thin gray or white discharge + fishy odor:
BV is a common possibility.

Thick, clumpy white discharge + significant itching:
A yeast infection is more typical.

Yellow-green or frothy discharge + irritation or painful urination:
Trichomoniasis is one possibility and requires STI testing and treatment.

Strong odor + pelvic pain, fever, or abnormal bleeding:
That needs medical evaluation rather than self-treatment.

The wrong treatment will not fix the underlying problem. Yeast creams treat fungal infections; they do not treat BV.

If you have a new sexual partner or possible STI exposure, testing can also be important. BV is not classified as an STI, but sexual activity is associated with BV, and having BV is associated with increased risk of acquiring certain STIs.

What actually clears a BV smell?

If you have symptomatic BV, the treatment that clears the underlying bacterial imbalance is an appropriate antibiotic.

The CDC's recommended regimens include:

• Metronidazole 500 mg by mouth twice daily for 7 days
• Metronidazole 0.75% vaginal gel once daily for 5 days
• Clindamycin 2% vaginal cream at bedtime for 7 days

Other treatment options are available in certain situations. The right choice depends on your symptoms, medical history, pregnancy status, allergies, previous treatment, and whether BV has come back before.

The odor often begins improving within a few days after effective treatment starts. If the smell is not improving, becomes stronger, or comes back soon after treatment, do not assume you simply need to wait longer. Persistent symptoms can mean the diagnosis needs to be confirmed again or that recurrent BV needs a different treatment strategy.

And do not use leftover antibiotics or someone else's prescription. A medication that worked for a previous episode may not be the right treatment for what is causing the symptoms now.

If you are prescribed antibiotics, take them exactly as directed by your clinician.

What about probiotics, yogurt, or garlic?

These are commonly suggested online, but they should not replace antibiotic treatment for symptomatic BV.

The CDC notes that studies of probiotics have not established them as a replacement or reliable adjunctive treatment for BV.

And putting yogurt, garlic, or other homemade treatments inside the vagina can cause irritation without treating the underlying bacterial imbalance.

If you want to try a supplement alongside treatment, ask your clinician rather than assuming it will clear the infection.

What if the BV smell keeps coming back?

This is where BV gets frustrating.

You can take the correct antibiotic, see the odor disappear, and then notice the same fishy smell again weeks or months later. Recurrence is common, and it does not mean you caused it by doing something wrong.

For a first recurrence, a clinician may retreat with the same recommended regimen or choose another recommended regimen.

If BV keeps returning, treatment becomes more individualized. Options can include longer-term suppressive therapy, such as metronidazole gel used twice weekly for several months. For people with multiple recurrences, some treatment plans also use an initial antibiotic course followed by vaginal boric acid and suppressive metronidazole. These approaches should be discussed with a clinician rather than started on your own.

What about treating a sexual partner?

This is one area where the guidance has changed.

Historically, routine treatment of male sexual partners was not recommended because earlier studies did not show a clear reduction in recurrence.

Newer evidence has changed the conversation. In October 2025, ACOG issued a Clinical Practice Update recommending that clinicians consider concurrent treatment of male sexual partners for adults with recurrent, symptomatic BV. ACOG also supports shared decision-making in some other partner situations while more research is developed.

That does not mean every person with BV needs to have their partner treated.

It does mean that if your BV keeps returning despite appropriate treatment, partner treatment is now a reasonable topic to bring up with your clinician.

If you have recurrent BV, ask about:

• Confirming that the recurring symptoms are actually BV
• Testing for other vaginal infections or STIs when appropriate
• Suppressive treatment if you have multiple recurrences
• Whether partner treatment is appropriate in your situation
• Whether sexual activity may be contributing to repeated recurrences

The goal is not simply to keep prescribing another short antibiotic course every time the smell returns. The goal is to reduce the cycle of recurrence.

When a BV smell needs more than watchful waiting

Most cases of BV are not emergencies. But certain symptoms mean you should get evaluated sooner.

Seek urgent medical care if you have:

• Severe pelvic or lower abdominal pain
• Fever or chills with pelvic pain
• Heavy vaginal bleeding that is not your normal period
• Severe pain or rapidly worsening symptoms

These symptoms can point to conditions other than uncomplicated BV, including pelvic inflammatory disease.

Arrange a medical visit soon if:

• You are pregnant and develop a new vaginal odor or change in discharge
• You have pelvic pressure, cramping, or other concerning symptoms during pregnancy
• You have yellow-green or frothy discharge
• You have genital sores
• You have painful urination
• You have had a new sexual exposure and could have an STI
• The odor returns shortly after finishing treatment
• Symptoms are not improving with treatment

Symptomatic BV during pregnancy should be evaluated and treated by a clinician. BV has been associated with adverse pregnancy outcomes, including preterm birth and premature rupture of membranes.

What about boric acid?

Boric acid sometimes appears in treatment plans for recurrent BV, but that does not make it a first-line treatment for a new fishy odor.

It is for vaginal use only and should never be swallowed. It should also not be used during pregnancy unless a clinician specifically tells you to do so.

If you are unsure whether you have BV, yeast, or an STI, get the diagnosis first instead of trying several vaginal products one after another.

Can you get rid of a BV smell overnight?

Usually, no.

There is no reliable wash, spray, home remedy, or over-the-counter product that can safely eliminate the underlying cause of BV overnight.

You may be able to temporarily cover the odor, but that is not the same as treating BV.

The fastest reliable approach is to get evaluated and, if BV is confirmed, start the appropriate prescription treatment. The odor often becomes noticeably better within the first few days of effective treatment.

If you need care quickly and your symptoms are straightforward, August  connects you with a US-licensed clinician who can review your symptoms and determine whether prescription treatment is appropriate.

There is an important limitation: an online visit cannot perform a pelvic examination, vaginal pH testing, or microscopy. If your symptoms are unclear, severe, recurrent, or suggest an STI, you may need an in-person evaluation.

You can also compare online BV treatment services and what each actually sends if you are deciding between telehealth options.

Conclusion

A BV smell is not a sign that you are dirty. It comes from a change in the vaginal bacterial balance: protective Lactobacillus bacteria decrease, vaginal pH rises, and BV-associated bacteria produce volatile compounds with that familiar fishy odor.

Washing more will not fix it. Douching can actually make the problem worse.

If you have symptomatic BV, the treatment that clears the underlying problem is an appropriate antibiotic. If the odor does not improve, keeps returning, or comes with pain, fever, abnormal bleeding, pregnancy, or possible STI exposure, it is time to look beyond a simple BV episode.

And if this keeps happening, do not just keep treating the smell. Ask why the BV is coming back. Current guidance now includes a conversation about suppressive treatment and, for some adults with recurrent symptomatic BV, whether concurrent sexual-partner treatment makes sense.