A fishy odor from vaginal discharge is usually noticeable right away because it is quite different from the usual natural scent. Sometimes it is present all the time, while in other cases it seems to appear “out of nowhere” after sex or becomes more noticeable during a period. The discharge itself may also change – becoming thinner, heavier, grayish, or yellowish. But the opposite is also possible: aside from the odor, a woman may have no other symptoms at all.
It can be especially frustrating when a shower helps only briefly and the odor returns a few hours later. The first thought in this situation is understandable – wash more thoroughly, switch intimate hygiene products, or try rinsing the vagina with something. In practice, a fishy odor is rarely a matter of inadequate hygiene, so it is more important to understand where it comes from and what can actually help get rid of it.
What Can Cause a Fishy Odor From Vaginal Discharge and Why Can It Become Stronger?
The cause cannot be determined from odor alone, although some conditions do have fairly recognizable features. It matters whether the discharge itself has changed, whether there is itching, burning, or pain, when the odor first appeared, and when it tends to become stronger.
Sometimes the explanation is quite simple. For example, a suddenly strong unpleasant odor can be caused by a tampon that has been forgotten inside the vagina. But when the discharge has a distinctly fishy odor, one of the first possibilities to consider is a change in the vaginal microbiome.
Why Is a Fishy Odor So Often Associated With Bacterial Vaginosis?
Bacterial vaginosis is one of the most characteristic causes of a fishy odor. With this condition, the usual balance of bacteria in the vagina changes: the number of lactobacilli decreases, while certain other bacteria begin to predominate. This is also what explains the unusual odor. Some bacteria produce volatile substances called amines, which create the characteristic smell often described as fishy.
With bacterial vaginosis, vaginal discharge often becomes thinner and more uniform, white or grayish-white, and sometimes more abundant. But there does not have to be gray discharge or any other “classic” sign. For some women, the odor itself is the most noticeable change.
The same applies to itching and burning. These symptoms are not required for bacterial vaginosis, so it is entirely possible to have an unpleasant odor without any itching or pain, and this does not rule out an imbalance in the vaginal microbiome.
Bacterial vaginosis itself is not considered a classic sexually transmitted infection (STI). This is important because when the odor appears after starting a new relationship, it can immediately raise concerns about the partner. At the same time, there is a real association with sexual activity: bacterial vaginosis is more common after having a new sexual partner, with multiple partners, and with sex without a condom. But this does not mean that one person simply “gave the other person bacterial vaginosis” in the way some STIs are transmitted.
Can a Fishy Odor Be a Sign of a Sexually Transmitted Infection?
Yes, that is possible. When a fishy or simply very unpleasant odor occurs together with changes in vaginal discharge, trichomoniasis is one condition that needs to be considered. Unlike bacterial vaginosis, trichomoniasis is a sexually transmitted infection caused by Trichomonas vaginalis.
With trichomoniasis, vaginal discharge may become more abundant, thin, yellowish or greenish, and sometimes frothy. Itching, burning, irritation, discomfort with urination, or pain during sex may also occur.
However, the absence of these symptoms does not completely rule out trichomoniasis. According to European sources, approximately 70–85% of infected women either have no symptoms at all or have symptoms so mild that the infection can remain unnoticed for a long time.
That is why a new sexual partner or sex without a condom is relevant information if unusual odor and discharge appear afterward. This does not mean that a woman is expected to diagnose an STI herself, but in this situation testing for sexually transmitted infections may be necessary.
It is also worth distinguishing this situation from a yeast infection, which women often suspect and begin treating on their own whenever vaginal discharge changes. Vulvovaginal candidiasis is not an STI, and it is much more commonly associated with significant itching, burning, irritation, and thick white discharge. A pronounced fishy odor is not a typical sign of a yeast infection.
Why Does the Odor Become Stronger After Sex or During a Period?
This is one of the features that can be particularly confusing. Before sex, the odor may have been barely noticeable, but afterward it suddenly becomes strong enough that a woman notices it for the first time. The natural assumption is that the problem began because of the sexual contact.
But with bacterial vaginosis, sex may not create the problem – it can simply make an existing one much more noticeable.
The normal vaginal environment is acidic. Semen has a higher pH, so after sex without a condom it temporarily makes the vaginal environment less acidic. Under these conditions, the characteristic amine odor associated with bacterial vaginosis can become stronger.
A similar situation can occur during a period. Menstrual blood also temporarily changes the acidity of the vaginal environment, and an odor that is barely noticeable on other days may become significantly stronger. It may decrease again after menstruation ends.
What Should You Do if Your Vaginal Discharge Smells Fishy?
It is completely understandable to want to get rid of the odor first and figure out where it is coming from afterward. This is especially true if it interferes with everyday life or a woman is worried that her partner may notice it. But it is important to separate two goals – what can be done safely right now and what can actually help eliminate the odor long term.
Can You Get Rid of the Odor at Least Temporarily?
A regular shower can temporarily make the odor less noticeable because it washes discharge off the skin and external genital area. That is enough. The external genital area can be washed with warm water, and if an intimate hygiene product is used, it is better to choose one that is mild and does not have a strong fragrance.
If the discharge has become heavier and is staining underwear, an ordinary unscented panty liner can be used and changed as needed. This is for comfort, not treatment.
There is no benefit to washing repeatedly or every time the odor returns. If it comes back a few hours after a shower, this does not mean that a woman has somehow become “not clean enough” during that time. External hygiene removes discharge from the skin but does not affect the reason its odor has changed.
After sex, a regular shower is also enough. There is no need to rinse inside the vagina in an attempt to remove semen and the odor along with it. During a period, menstrual hygiene products should be changed regularly. A tampon is generally changed every 4–8 hours and should not be left in the vagina for more than 8 hours.
If the odor is actually related to bacterial vaginosis, trichomoniasis, or another condition, the only way to get rid of it consistently is to address the underlying cause. Products that promise to “neutralize intimate odor” do not solve that problem on their own.
Why Can Douching and “Microbiome” Products Make Things Worse?
When the odor seems to be coming from inside the vagina, the idea of rinsing the vagina itself can seem quite logical. From a medical standpoint, however, this is a poor solution.
Douching with water, baking soda, chlorhexidine, or other antiseptics does not restore a normal vaginal microbiome. On the contrary, this kind of intervention alters the vaginal environment, and douching itself is associated with bacterial vaginosis and its recurrence. There is no way to wash out only the “wrong” bacteria while leaving everything else unchanged.
For the same reason, vaginal deodorants, scented wipes, and fragranced gels should be avoided. They may mask the odor temporarily, but they do not eliminate its source and can sometimes cause additional irritation of the skin and mucous membranes.
I also do not recommend starting treatment at random. Yeast infection suppositories do not treat bacterial vaginosis or trichomoniasis. An antiseptic is not a universal treatment for changes in vaginal discharge. Products marketed to “restore the vaginal microbiome” are also no substitute for understanding what has actually happened to that microbiome.
Even if bacterial vaginosis was previously diagnosed when a woman had what seemed to be exactly the same odor, using leftover medication or repeating an old treatment regimen on her own is not the best approach. Similar symptoms do not guarantee the same underlying cause.
When Should You Make an Appointment With a Gynecologist?
If a fishy odor appears for the first time and does not go away, returns soon after normal hygiene, or is accompanied by a noticeable change in vaginal discharge, it is not worth waiting several weeks in the hope that the problem will resolve on its own. If you otherwise feel well, a routine appointment is usually appropriate.
Before the appointment, it can be useful simply to observe what is happening without trying to diagnose yourself:
- When did the odor first appear?
- Is it constant or intermittent?
- Does it become stronger after sex or during your period?
- Has the color, amount, or consistency of the discharge changed?
- Is there itching, burning, pain, or discomfort with urination?
- Have you had a new sexual partner or sex without a condom?
These details can genuinely help your doctor determine what kind of evaluation is appropriate.
There is no need to order a large panel of “vaginal microbiome” tests on your own before the appointment. Depending on the situation, the doctor may evaluate the discharge and vaginal tissues, assess the acidity of the vaginal environment, or collect a sample for microscopic or laboratory testing. If there is reason to suspect trichomoniasis or another STI, testing can then be directed toward specific infections.
A fishy odor by itself is usually not a reason to seek emergency care. But the situation changes if it is accompanied by severe or worsening lower abdominal pain, a temperature of 100.4 °F (38 °C) or higher, bleeding outside an expected period, or a noticeable decline in your overall condition. In that situation, it is better not to wait for a routine appointment.
During pregnancy, a new pronounced odor and a change in vaginal discharge should also be discussed with a doctor even if there is no pain. Symptomatic bacterial vaginosis during pregnancy requires treatment, so it should not simply be observed until the next routine prenatal visit.
Why Can a Fishy Odor Return After Treatment?
Bacterial vaginosis has a tendency to recur, and this is one of its most frustrating features. Even after appropriate treatment, the fishy odor and abnormal discharge may disappear and then return some time later.
The reason is that treating the current episode and achieving a stable restoration of the normal vaginal microbiome are not quite the same thing. Medications suppress the bacteria associated with bacterial vaginosis and the symptoms resolve, but the protective predominance of lactobacilli does not recover equally quickly or remain equally stable in every woman. If the balance shifts again, the characteristic symptoms can return.
There is another reason that is receiving considerable attention. With bacterial vaginosis, bacteria can form what is known as a biofilm on the vaginal lining – an organized community of microorganisms that adheres to the surface of the epithelium. This structure may persist after treatment and is considered one of the mechanisms that can contribute to recurrent bacterial vaginosis.
Therefore, the return of a fishy odor after treatment does not automatically mean that the medication “did not work,” that the treatment was incorrect, or that a woman did not maintain adequate hygiene. Bacterial vaginosis itself has a tendency to recur, and when episodes keep returning, a doctor may consider a different and longer-term treatment approach than would be used for an isolated episode.
A fishy odor from vaginal discharge is not a matter of inadequate cleanliness. Most often, it is associated with a change in the vaginal microbiome, particularly bacterial vaginosis, although other causes are possible. Until the cause is known, regular external hygiene without douching, antiseptics, or treatment at random is enough. If the odor persists or returns, the only way to get rid of it long term is to first understand why it appeared.
Clinical Guidelines and Sources
- World Health Organization (WHO). Bacterial Vaginosis. Current information on the causes, symptoms, diagnosis, treatment, and risk factors of bacterial vaginosis.
- CDC. Sexually Transmitted Infections Treatment Guidelines – Bacterial Vaginosis. Clinical guidelines for the diagnosis and treatment of bacterial vaginosis, including the management of recurrent cases.
- CDC. Sexually Transmitted Infections Treatment Guidelines – Trichomoniasis. Recommendations on the clinical manifestations, diagnosis, treatment, and prevention of reinfection with trichomoniasis.
- IUSTI. European Guideline on the Management of Vaginal Discharge. European guidelines for the diagnosis and management of conditions associated with changes in vaginal discharge.