What Causes Vaginal Odor?The Main Culprits, Sorted by Where the Smell Comes From

You notice it at the end of a long day, when you peel off your jeans. Or ten minutes after sex. Or on day two of your period, when the smell turns faintly metallic, like a handful of coins.

Your vagina is supposed to smell like something

A healthy vagina has a scent. Cleveland Clinic¹ describes the usual range as sour or tangy, sometimes a little like sourdough, and credits that tang to lactobacilli, the “good” bacteria that keep things acidic. A typical vaginal pH sits between 3.8 and 4.5.

That acidity is the guard at the door. It keeps the bacteria that cause trouble from taking over.

So most odor questions come down to one thing. What nudged the pH up?

Some nudges are routine. The hormonal swings of your cycle, pregnancy, and menopause all move vaginal pH, and so do semen, antibiotics, and douching. A pH a little above 4.5 can be normal right before your period and after menopause. Period blood brings its own note, that copper-penny smell, from the iron in blood. We cover period smell and semen in their own articles, so here’s the short version: a temporary shift after sex or during your period is fine by itself.

A fishy smell tends to go with bacterial vaginosis

If the smell is fishy, the first suspect is bacterial vaginosis, or BV. The CDC² calls it the most common vaginal condition in women ages 15 to 44, and Cleveland Clinic³ estimates about 35% of people with a vagina will get it.

What happens is an overgrowth. The usual bacterial mix tips out of balance and other bacteria crowd in.

The fish part is literal chemistry. A 2002 study⁴ in the journal APMIS traced the odor to bacteria converting a compound called trimethylamine oxide into trimethylamine. The researchers found trimethylamine in every woman whose lab smear scored in the highest BV range, and little to none in women with normal results.

Clinicians check for BV by adding an alkaline solution to a sample of discharge, which releases that trimethylamine and the fishy smell with it. And BV tends to smell strongest after sex.

The CDC² names douching, not using condoms, and new or multiple sex partners as things that raise BV risk. The NHS⁵ adds having an IUD and using perfumed products in or around the vagina. BV isn’t classed as a sexually transmitted infection, though sex can trigger it or pass it on.

Half of women with BV have no symptoms at all, the NHS⁵ reports, so smelling fine doesn’t rule it out. And a fishy smell doesn’t mean you’re dirty. It means the bacterial balance moved.

If you have symptoms, the CDC² says to get checked and treated, though BV sometimes clears up on its own. Untreated BV raises the chance of getting HIV and other STIs like chlamydia and gonorrhea, and in pregnancy it raises the chance of premature birth or low birth weight. Treatment is prescription antibiotics, as tablets, gel, or cream.

It’s common for BV to come back within a few months, according to the NHS⁵. If the fishy smell returns after treatment, go back to your clinician instead of retreating yourself. And if you’re pregnant and think you have BV, see a doctor.

Fishy or musty with a color change: trich is a suspect too

Trichomoniasis, a sexually transmitted infection caused by a parasite, can smell fishy like BV or more musty, per Cleveland Clinic¹. The CDC⁶ estimates there were more than two million trich infections in the United States in 2018. About 70% of people who have it notice no signs at all.

When trich does show up in women, it can bring a thin or heavier discharge that’s clear, white, yellowish, or greenish, with a fishy smell.

Can you tell BV from trich by sniffing? No. Trich can’t be diagnosed on symptoms alone, and a lab test confirms it. Good news, though: it’s treatable with prescription medicine taken by mouth. Sex partners need treatment at the same time so it doesn’t pass back and forth, and the CDC⁶ advises no sex until you’ve both finished.

Gonorrhea can also give discharge a strong odor, which is one more reason to test instead of sniff.

Itchy and clumpy with no smell is a different story

Yeast gets blamed first, and it’s usually innocent of the smell. The NHS⁷ describes thrush discharge as white, “often like cottage cheese,” and notes that it does not usually smell.

That matters at the drugstore. An antifungal treats yeast. If it’s your first time, you’re pregnant, you’re not sure it’s yeast, or it keeps coming back, get checked before you buy anything. And if the main problem is a strong fishy odor, the clue is pointing somewhere else. A clinician can sort out which infection, if any, you have.

Sometimes it isn’t the vagina at all

Some of what reads as vaginal odor comes from the vulva and groin. Part of the sweat in your groin comes from apocrine glands, and Cleveland Clinic⁸ notes that this sweat is thicker and richer in fat and protein than sweat elsewhere on your body. Sweat has no odor on its own. None. It picks one up when it meets the bacteria on your skin.

Picture leggings after a spin class, or a long summer car ride in denim. That’s sweat and skin bacteria doing what they do, and it tends to fade once you rinse with water and change into dry underwear.

A skunky, body-odor smell tends to go with stress and overactive sweat glands. An ammonia smell can be a sign of urine residue on the vulva or of being dehydrated, per Cleveland Clinic¹.

A bleach-like smell is a different matter. Discharge can take on that smell with a urinary tract infection, so if it hangs around or comes with burning when you pee, get it checked.

Food can briefly change how your sweat and urine smell, too, which can turn up the volume down there for a day. Our article on vaginal versus vulvar odor goes further into telling the two apart.

Something left behind

A smell like rotting meat is the classic sign of a forgotten tampon. It happens. A heavy day blurs together, or a second tampon goes in before the first came out.

The FDA⁹ says to change each tampon every 4 to 8 hours and never wear one for more than 8. Stuck and can’t get it out? Get seen soon instead of waiting it out.

Far less common causes of foul-smelling discharge include a rectovaginal fistula (an abnormal opening between the rectum and vagina), vaginal cancer, and cervical cancer. These are rare. A smell that won’t leave is a reason for an exam, not a guess.

The products sold to fix odor can backfire

Douching is a bad idea, full stop. Cleveland Clinic¹ says it can upset vaginal pH and leave you open to infection, and the CDC² counts it as a BV risk factor.

The NHS⁵ goes further and advises skipping perfumed soaps, vaginal deodorants, antiseptic liquids, and strong detergents on underwear, and sticking with water and plain soap.

Which makes for a strange loop. A product sold to cover a smell can irritate the skin and nudge the pH up, and a higher pH is the opening BV needs.

For lubricant, go unscented and unflavored. We break down washing, feminine washes, and douching in separate articles.

When to get checked

Don’t wait if

1. Emergency

   Some signs can’t wait for an appointment. During or soon after your period, a sudden fever of 102°F or higher, vomiting, diarrhea, dizziness, fainting or nearly fainting when you stand, or a rash that looks like sunburn can be signs of toxic shock syndrome, the FDA⁹ says. Take the tampon out and go to urgent care or the ER, or call 911 or your local emergency number. Fever with pelvic pain also needs prompt care.

2. Urgent

   Pregnant and noticing bleeding, a gush or steady trickle of fluid, fever, or cramping? Call your pregnancy care provider right away or go to labor and delivery.

Cleveland Clinic⁸ advises seeing a healthcare provider for an abnormal odor that sticks around, or odor that comes with discharge, burning, or itching. Make an appointment if you notice:

• A fishy, musty, or rotten smell that’s new and doesn’t go away
• Odor along with a change in discharge color, amount, or texture
• Itching, burning, swelling, or pain when you pee
• Pain during sex, pelvic pain, bleeding between periods or after sex, or any bleeding after menopause
• A smell that changed in character or strength along with any of the above
• Pregnancy plus any new odor or discharge
• A new partner, or any chance you were exposed to an STI, since about 70% of people with trich notice no signs