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8 Causes of Fishy Vaginal Odor and What to Do About It

If you’ve noticed an unpleasant smell coming from your vagina, something may not be quite right. Below, Flo outlines some possible causes of a fishy vaginal odor, along with expert tips on how to tackle it. 

What causes a fishy vaginal odor?

We’ve listed nine possible reasons for developing a fishy vaginal odor, each with its own unique set of symptoms and treatments. In some cases, you might be able to resolve the issue with simple at-home remedies. So what exactly causes a fishy vaginal odor? 

1. Bacterial vaginosis

Bacterial vaginosis (BV) is one of the main culprits behind a fishy vaginal odor. People who are at a fertile age sometimes experience it after intercourse, although it’s not a sexually transmitted infection (STI). BV is instead the result of a bacterial imbalance of vaginal flora (specifically, Gardnerella vaginalis and Bacteroides). Aside from a fishy vaginal odor, BV also produces itching and a thin white, grey, yellow, or green-colored discharge.

Although BV is relatively common, you should have it treated as soon as possible because it increases the likelihood of other genital infections and STIs. Research shows that BV during pregnancy increases the chances of preterm premature rupture of membranes, preterm delivery, and postpartum infections (e.g., chorioamnionitis and endometritis). Your health care provider will prescribe antibiotics to clear up BV and may suggest a topical solution to alleviate associated symptoms.

2. Trichomoniasis or other STIs

A fishy vaginal odor could potentially arise if you’ve contracted an STI like trichomoniasis. According to the Centers for Disease Control and Protection, it affects 3.7 million people across the United States. 

Also known as “trich,” it occurs when a protozoan parasite called Trichomonas vaginalis is transmitted during intercourse. Anyone can get it, and it presents symptoms such as genital itching and painful urination and intercourse. If you have trichomoniasis, you may detect a fishy vaginal odor, frothy yellow-green discharge, and vaginal soreness and swelling. 

However, only 30 percent of people with trichomoniasis display any symptoms. That’s why it’s crucial to get regular STI screenings if you’re having sex with different partners. Please do not attempt to diagnose or treat trichomoniasis at home. If ignored, it can create serious complications like pelvic inflammatory disease (PID) or preterm birth if you’re pregnant.

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3. Pelvic inflammatory disease

Pelvic inflammatory disease is another possible explanation for a fishy vaginal odor. It’s essentially a vaginal infection that spreads upwards into your pelvis and reproductive organs, including your uterus, fallopian tubes, and ovaries. An estimated 1 million cases are reported annually in the United States.

PID can carry long-term consequences, causing 1 in 10 women to become infertile. This is especially true for people with recurring episodes of PID. PID also makes you more likely to have an ectopic pregnancy because it makes it harder for a fertilized egg to move through the fallopian tubes into the uterus.

People with PID might notice a fishy vaginal odor during sex, along with bleeding triggered by intercourse. Consult your health care provider if you see any such symptoms.

4. Excessive sweating

Perspiration is the body’s way of cooling itself down when it’s overheating. Sweating while engaging in a vigorous activity is common, as is sweating due to stress or anxiety. A fishy vaginal odor could be the result of sweating in the pelvic area.

You can battle odor from excessive sweating by improving your overall hygiene, wearing natural fabrics, and layering clothing. In extreme instances, a sweat-induced fishy vaginal odor may point to a medical condition called trimethylaminuria, which you should discuss with a health care professional.

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5. Unhealthy diet

If your natural pH levels are in balance, you are less likely to notice a fishy vaginal odor. Certain influences, like your diet, can positively or negatively affect this balance. Be sure to eat a nutritious diet full of vitamins and minerals to keep everything in tip-top shape.

6. Poor hygiene

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If you notice a fishy vaginal odor with no discharge and/or itching, you may be able to solve the problem by practicing good hygiene. This includes:

  • Wiping from front to back after peeing and pooping
  • Urinating after intercourse
  • Changing your underwear once a day (or more if you sweat a lot)
  • Using unscented laundry detergent to wash your underwear
  • Bathing/showering your entire body with a gentle cleanser

After discovering a fishy vaginal odor, it may be tempting to vigorously clean the inside of your vagina or try to mask the smell. But the truth is, these chemicals will alter your vaginal pH, which could make the situation worse and lead to an infection. 

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7. An old tampon

A foul, fishy vaginal odor could arise if you’ve left a tampon in for too long. Change your tampons and pads regularly, according to your menstrual flow. Choose a period product with the right amount of absorbancy for your flow that day. Tampons with a higher-than-necessary absorption can often lead to dryness.

Leaving a tampon in for too long can result in a slight chance of developing toxic shock syndrome. If you’ve left a tampon in for too long, try to carefully remove it as soon as possible. Seek medical attention if you can’t remove it or if you suddenly experience a high fever, vomiting, diarrhea, or sunburn-like rashes.

8. Menstrual cycle

Sometimes, a fishy vaginal odor crops up just before the start of your period, due to changing bacteria and acidity levels. During menstruation, the blood (which has an elevated pH) and uterine lining mix with vaginal microflora, subtly altering the smell. Because of this, you might also notice a fishy vaginal odor after your period. It’s nothing to worry about as long as it isn’t due to a forgotten tampon.

Lastly, hormonal shifts during menopause can also influence your scent and lead to dryness, potentially causing a fishy vaginal odor.

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Treating fishy vaginal odors

As long as a fishy vaginal odor is not accompanied by discharge, it’s possible to address the issue with a few at-home remedies:

Switch to gentle, fragrance-free cleansers

Avoid scented soaps, bubble baths, and vaginal deodorants, which further destroy the delicate balance of your vaginal flora. Gently cleanse your vulva with unscented products and/or plain water. Never use harsh soaps or try to clean the inside of your vagina. Additionally, consider researching hygienic tips to improve your vaginal odor.

Avoid douching

You should only use douches if your health care provider specifically prescribes them and only when medically necessary. They tend to aggravate fishy vaginal odors and compromise your vagina’s natural self-cleaning ability.

When to see a health care provider for fishy vaginal odor

If you have a fishy vaginal odor that won’t go away even after trying the techniques above, it’s time to see a health care professional. This is also true if the fishy vaginal odor comes with any itching, burning, or bleeding.

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FAQs on fishy vaginal odor

Still have questions about fishy vaginal odors? Never fear, because Flo is here to answer them all.

Does chlamydia create a fishy vaginal odor?

No, not usually. Chlamydia is a very common STI that sometimes goes undetected. Though it can result in a case of vaginitis, it generally remains ​odorless.

What does a fishy vaginal odor after sex mean?

A fishy vaginal odor after unprotected sex isn’t unusual as long as the smell is subtle and goes away after bathing. 

Just be on the lookout for other symptoms like itching or burning brought on by the mixture of vaginal discharge and sperm. Furthermore, if the smell lingers or becomes stronger, it may point to BV or an STI.

Should I be concerned about a fishy vaginal odor during pregnancy?

While pregnant, a fishy odor either in your urine or vaginal discharge is a potential sign of a urinary tract infection or BV. Left untreated, the condition could lead to preterm birth or low birth weight.

Following childbirth, the development of a fishy vaginal odor may be from a postpartum infection. Please make an appointment to see your health care provider to follow up.


Every healthy vagina possesses a unique and subtle smell, which ordinarily goes unnoticed by everyone but you. 

However, if a fishy vaginal odor is accompanied by itching, burning, pain, or bleeding, seek medical assistance right away. Your health care provider will perform the necessary lab screenings to diagnose and treat a fishy vaginal odor. 

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