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why does my vagina smell like fish

A strong fishy smell from the vagina is usually a sign that something is off with the normal balance of bacteria, and it is very often treatable with proper medical care.

Quick Scoop

  • The most common cause is bacterial vaginosis (BV) , an imbalance of vaginal bacteria that leads to a noticeable fishy odor, especially after sex.
  • Sexually transmitted infections like trichomoniasis can also cause a fishy or foul smell plus itching, burning, and unusual discharge.
  • A forgotten tampon or other object in the vagina can create a very strong rotten or fishy smell and needs urgent removal by a doctor.
  • Very rarely, a metabolic condition called trimethylaminuria can cause body, urine, and vaginal secretions to smell like rotten fish.

If the smell is strong, new, lasts more than a couple of days, or comes with itching, burning, pain, or unusual discharge, you should see a clinician as soon as you can.

What’s “normal” vs “not normal”?

A healthy vagina has a natural scent that can change with your cycle, sex, sweat, or exercise, but it usually is mild and not sharply fishy. A sudden or persistent fishy or rotten smell is not considered normal and usually signals infection or another medical issue.

Signs it may be a problem:

  • Strong fishy smell that doesn’t go away after washing.
  • Smell that is worse after sex or during your period.
  • Itching, burning, soreness, or pain with peeing or sex.
  • Gray, white, yellow, or green, or foamy discharge.

Common causes of a fishy smell

1. Bacterial vaginosis (BV)

BV is the number one medical cause of a fishy vaginal odor in people of reproductive age. It happens when the normal lactobacillus bacteria are outnumbered by other bacteria, which produce amines like trimethylamine that smell like spoiling fish.

Typical features:

  • Thin gray‑white discharge
  • Strong fishy smell, often stronger after sex or around your period
  • Sometimes mild itching or irritation, but many people have no other symptoms

BV needs prescription antibiotics (oral or vaginal) from a clinician; home remedies alone usually don’t reliably cure it.

2. Trichomoniasis (STI)

Trichomoniasis is a sexually transmitted infection caused by a parasite and is a well‑known cause of foul or fishy odor.

Common symptoms:

  • Strong odor plus frothy or foamy discharge that may be yellow‑green
  • Itching, burning, redness, or swelling around the vulva
  • Pain during sex or when peeing

It is treatable with specific antibiotics, and sexual partners usually need treatment too.

3. Forgotten tampon or object

A tampon accidentally left in for days can cause an extremely strong fishy or rotten smell and sometimes blood‑streaked or brown discharge. If you think there might be a tampon or other object stuck, do not ignore it; it must be removed promptly to avoid serious infection.

4. Sweat, hygiene, and products

The vulva (outside) has sweat glands and can trap moisture, which can mix with normal secretions and cause stronger odor, especially after exercise or in tight synthetic underwear. Strong soaps, douches, and scented products can irritate tissue and disrupt the natural pH, increasing the risk of BV and odor.

5. Rare metabolic cause (trimethylaminuria)

Trimethylaminuria (“fish odor syndrome”) is a rare genetic condition where the body cannot break down trimethylamine, the same chemical responsible for rotting fish smell. This leads to breath, sweat, urine, and vaginal secretions all having a strong fishy odor, often getting worse around menstruation or hormonal changes.

What you can do right now

Self-care can help with mild odor, but anything strong, persistent, or accompanied by other symptoms deserves professional evaluation.

Do:

  • Gently wash the vulva (outer area) with lukewarm water; if needed, use a mild, unscented cleanser on the outside only.
  • Wear breathable cotton underwear and avoid tight, non‑breathable leggings or underwear for long periods.
  • Change out of wet clothes (swimsuits, gym wear) promptly.
  • Use condoms or barriers with new partners to lower risk of STIs and BV.

Avoid:

  • Douching (rinsing inside the vagina) – this actually increases the risk of BV and worsens odor.
  • Scented wipes, sprays, powders, or perfumed soaps on or inside the vulva.
  • Trying to “mask” a strong smell with perfume instead of seeking care.

When to see a doctor or clinic

Seek medical care soon (urgent care, GP, gynecologist, or sexual health clinic) if:

  • The fishy smell is strong, new, or has lasted more than a few days.
  • You also have itching, burning, pelvic pain, pain with sex, or pain when peeing.
  • Discharge changes in color (gray, yellow, green), texture (foamy), or amount.
  • You may have been exposed to an STI or have a new partner.
  • You think a tampon or other object might be stuck and you can’t find or remove it.

A clinician can:

  • Do a pelvic exam and simple tests (swabs, pH, microscope) to check for BV, trich, and other infections.
  • Prescribe targeted antibiotics or other treatments that usually resolve the odor once the underlying cause is treated.

Bottom note: This information reflects general medical and forum‑discussion knowledge online and is not a substitute for an in‑person exam or personalized advice from a qualified clinician.