What Causes a ‘Fishy' Vaginal Odor and How Is It Treated?

Health Line

03-06-2025

A fishy or unusual vaginal odor isn't always a cause for concern. But if you're experiencing itching, pain, or other unexpected symptoms, it could point to an underlying condition like bacterial vaginosis.
A healthy vulva and vagina may smell a bit like blood or copper, somewhat salty or sweet, or musky. A fishy odor may even happen from time to time with no underlying cause.
In many cases, changing into a fresh pair of underwear after a bath or shower is enough to restore your usual odor.
An odor that lingers after a thorough wash or occurs alongside other unusual symptoms could warrant an appointment with a doctor or other healthcare professional.
Vaginal discharge, for example, is typically clear or slightly cloudy with a sticky, stringy consistency. In the days before menstruation, it might be closer to white than clear.
Discharge tinged with gray, yellow, or green could point to an underlying infection, especially when coupled with an unpleasant odor, itching, or burning.
Bacterial vaginosis (BV)
A lingering change in odor, particularly a foul or fishy scent, is most commonly caused by BV
Your body naturally contains a wide variety of bacteria, and your vulva and vagina are no exception. Although the body can usually maintain this delicate balance of bacteria, unexpected fluctuations can increase the risk of infection.
BV can develop in response to an overgrowth of certain bacteria. However, the exact cause is unclear. You may be more likely to develop bacterial vaginosis if you:
Other symptoms of bacterial vaginosis include:
thin vaginal discharge that's gray, white, or green
strong vaginal odor after sexual activity
pain during or after penetrative sex
pain or burning during urination
itching in or around the vagina
Trichomoniasis ('trich')
Trichomoniasis is a sexually transmitted infection (STI) caused by the Trichomonas vaginalis parasite.
People who have penises are generally asymptomatic, whereas people who have vulvas often experience symptoms.
In addition to a foul or fishy vaginal odor, trichomoniasis can cause:
increased vaginal discharge
foamy or frothy discharge
white, yellow, or green discharge
pain during or after penetrative sex
pain or burning during urination
itching in or around the vagina
redness around the vaginal opening
Dehydration
If you tend to notice the odor after you urinate, it could be a sign of dehydration.
Urine is primarily water, with a small percentage of urea and other waste. If you aren't well hydrated, waste may be more pungent than usual.
Urea, for example, is a byproduct of ammonia. It's often associated with a chemical-like smell, though some may describe it as fishy.
Sweat
Sweat-related body odor is often described as skunky, but this is ultimately subject to interpretation.
Consider your recent activity levels — anything from lugging groceries up the stairs to lifting weights in the gym — and when you last washed up or changed your clothes.
Your overall temperature, the fit and fabric of your clothes, and the weather outside can also contribute to genital sweating.
Hygiene
So-called 'feminine' hygiene products, like scented sprays and suppositories, can temporarily disrupt your overall vaginal pH.
This can result in inflammation and irritation that may, in turn, lead to the overgrowth of odor-causing bacteria.
Practices like douching and steaming can also alter the vagina's natural microbiome, increasing your risk of injury or infection.
Sexual activity
Solo or partnered play, with or without vaginal penetration, can also spur an unexpected change in scent. Condoms and lube, for example, can affect your vaginal pH. So can the exchange of bodily fluids.
Sex toys and other erotic aids can also introduce bacteria, particularly when shared or improperly cleaned.
Bacterial vaginosis and other underlying infections can exacerbate these symptoms, making your post-sex smell more pungent than usual.
Trimethylaminuria
In rare cases, a fishy odor may be the result of an inherited condition called trimethylaminuria.
Your body naturally produces trimethylamine (TMA) when breaking down certain foods. The strong-smelling chemical generally breaks down into a less fragrant compound, allowing your body to excrete TMA without notice.
People who have trimethylaminuria are unable to process TMA as expected. This can cause your breath, sweat, urine, or vaginal secretions to smell rotten or fishy.
The smell may intensify with hormonal fluctuations, including menstruation and menopause.
When should you consult with a doctor or other healthcare professional?
If you've had a prior bacterial vaginosis infection, you might be comfortable using an at-home test to assess your current symptoms.
You might also feel comfortable using an at-home STI test to check for trichomoniasis. This usually involves taking a urine sample to send to a lab. A healthcare professional will likely reach out to discuss a positive result.
If you're uncomfortable with at-home testing or unsure of your symptoms, it's important to consult with a doctor or other healthcare professional.
The following symptoms typically require medical intervention:
strong vaginal odor after sexual activity
gray, yellow, or green vaginal discharge
foamy, frothy, or increased vaginal discharge
soreness, burning, or itching
Your clinician will ask you questions about your symptoms, your medical history, and recent sexual activity to help identify the potential cause.
They'll likely perform a pelvic exam to check for inflammation and other abnormalities. Your clinician may also swab inside the vagina to take a fluid sample for lab testing. They may also ask you to provide a urine sample.
If you aren't experiencing symptoms but have concerns about your scent, consult with a gynecologist or other healthcare professional. They can answer any questions you may have and may be able to set your mind at ease.
What treatment options are available?
Although bacterial vaginosis can resolve on its own, antibiotics can help speed the process along and alleviate your symptoms. A healthcare professional may prescribe:
metronidazole, which can be applied topically or taken as a pill
clindamycin, which can be applied topically, inserted as a suppository, or taken as a pill
tinidazole, which is taken as a pill
secnidazole, which is taken as a powder mixed with food
Some over-the-counter products are marketed as effective treatments for bacterial vaginosis, but it's important to note that the Food and Drug Administration has not approved any over-the-counter method for use.
Trichomoniasis will not resolve without treatment. Your clinician will likely prescribe the oral antibiotic metronidazole.
Generally speaking, odor related to sweat, dehydration, and vaginal irritation can be managed with certain lifestyle changes. Limiting time spent in damp or wet clothes, washing more frequently, and staying hydrated can help.
Lifestyle changes may also help with trimethylaminuria. Consult with a healthcare professional to learn more.
What can you do to prevent unwanted vaginal odor?
Practicing good hygiene is the best way to prevent unwanted vaginal odor. Depending on your activity level, this may look like bathing or showering every day, every other day, or just a few times per week.
Warm water is all you need to cleanse your vulva, but you can also use a mild, fragrance-free soap.
Stick to the external bits — your vagina is a self-cleaning machine. Internal 'cleansers' like douches are more harmful than helpful.
When it comes to menstrual hygiene, keep an eye on the clock. Different products have different guidelines for the length of use. You may need to change your pad, tampon, cup, disc, or menstrual underwear more frequently.
Wash your hands before and after changing menstrual hygiene products. If you use a reusable method, be sure to check out the manufacturer's guidelines for care.
Avoid spending extended periods of time in sweaty clothes, particularly damp underwear or swimsuit bottoms. Wash up, pat yourself dry, and change into something dry as soon as possible.
Opt for breathable materials, like cotton, when selecting underwear. You might also consider sizing up on pants, shorts, and other bottoms for a looser fit or selecting clothes with an airy silhouette.
Adopting safer solo and partnered sex practices can also make a difference. Much like menstrual hygiene products, condoms, lubricants, sex toys, and other erotic aids have different guidelines for use.
Regular STI testing can help you stay on top of your status and, if needed, start treatment sooner rather than later.
The bottom line
Your vulva — which includes your labia and vaginal opening — smells differently throughout your menstrual cycle. Different forms of physical activity, recent food intake, and overall hydration can also affect your unique scent.
As long as you aren't experiencing other unusual symptoms, a change in smell may not be a sign of anything more. If the odor intensifies or lasts for more than a day or two, it could be related to an underlying infection or other health condition.