Vaginal Odor: What Is Normal and What Causes a Change

What normal vaginal odor is like

A healthy vagina contains Lactobacillus bacteria, which keep it slightly acidic (pH about 3.8 to 4.5). This produces a mild, slightly sour or tangy scent. It is normal for the smell to change:

• around your period, when blood can give a metallic smell
• after exercise and sweating, from the groin sweat glands
• after sex, because semen is alkaline
• with changes in hormones during pregnancy and menopause

The vagina cleans itself. Odor that is mild and does not come with discomfort or unusual discharge does not need treatment.

What different vaginal smells mean

Causes of vaginal odor

Bacterial vaginosis

Bacterial vaginosis (BV) is an overgrowth of bacteria that normally live in the vagina in small numbers, replacing the protective lactobacilli. It causes a fishy smell, often stronger after sex or during a period, and a thin, gray or white discharge. It is the most common cause of vaginal symptoms in women of reproductive age. It is not considered a sexually transmitted infection, but new or multiple sexual partners, douching and smoking raise the risk.

Trichomoniasis

Trichomoniasis is a common sexually transmitted infection caused by a parasite. It can cause a strong odor with frothy yellow-green discharge, itching, burning and pain during sex or urination. Many people have no symptoms. Partners need treatment too.

Retained tampon or object

A forgotten tampon, condom or contraceptive device causes a very strong, foul odor and brown discharge within days. Removing it usually clears the smell quickly. Rarely, it can lead to toxic shock syndrome.

Yeast infection

A vaginal yeast infection causes itching, soreness and thick white discharge, but usually little or no odor. If odor is the main symptom, BV or trichomoniasis is more likely.

Sweat and hygiene

Sweat glands in the groin, tight synthetic clothing, and wearing damp clothes or pads for long periods can create a stronger body odor around the vulva.

Menopause

Low estrogen after menopause thins the vaginal lining and raises pH, making infections and odor more likely. This is part of atrophic vaginitis (genitourinary syndrome of menopause), with dryness and discomfort.

Less common causes

• Pelvic inflammatory disease: odor with pelvic pain, fever and abnormal discharge.
• Cervical or vaginal cancer: rarely, a persistent foul-smelling, watery or bloody discharge, especially with bleeding after sex or after menopause.
• Fistula: an abnormal connection between the vagina and bladder or bowel.
• Diet: strong foods such as garlic and asparagus may subtly change body odors.

How the cause is diagnosed

A clinician will ask about the smell, discharge, itching, sexual partners, contraception, tampons, douching and your cycle. A pelvic exam checks for discharge, foreign objects and inflammation. A sample of discharge is tested:

• pH test: above 4.5 suggests BV or trichomoniasis
• "Whiff test": adding a drop of potassium hydroxide releases a fishy smell in BV
• Microscopy for "clue cells" (BV), yeast or trichomonads
• NAAT (molecular) tests for trichomoniasis, chlamydia and gonorrhea

Self-collected swabs and some home tests are available, but self-diagnosis is often wrong, so test before treating, especially the first time.

Treatment

• Bacterial vaginosis: prescription antibiotics, either metronidazole or clindamycin, as tablets or vaginal gel or cream. Recurrence within 3 to 12 months is common. Longer suppressive treatment helps frequent recurrences.
• Trichomoniasis: metronidazole or tinidazole for you and your partners. Avoid sex until everyone is treated and symptoms have gone.
• Retained tampon: remove it if you can, or see a clinician.
• Yeast infection: antifungal creams, pessaries or tablets.
• Menopause-related changes: vaginal moisturizers and low-dose vaginal estrogen.

How to prevent vaginal odor

• Do not douche. Douching washes away protective bacteria and raises the risk of BV and other infections.
• Wash the vulva (outside only) with warm water and, if you like, a mild unscented soap.
• Avoid scented washes, wipes, sprays, bubble baths and deodorant pads.
• Wear breathable cotton underwear, and change out of sweaty or wet clothes promptly.
• Change tampons every 4 to 8 hours and pads regularly. Use the lowest absorbency you need.
• Use condoms, which reduce BV recurrence and STIs.
• Wipe from front to back.

Frequently asked questions

What causes a fishy vaginal odor?

A fishy smell is the classic sign of bacterial vaginosis, an imbalance of the normal vaginal bacteria. It is often stronger after sex or during a period and comes with thin gray-white discharge. Trichomoniasis can also cause a fishy odor. Both are easily diagnosed and treated with prescription antibiotics.

Why does my vagina smell after sex?

Semen is alkaline, so it temporarily raises vaginal pH and can make an existing imbalance smell stronger, especially a fishy odor from bacterial vaginosis. A mild change that goes within a day is normal. A persistent fishy smell after sex should be tested for BV or trichomoniasis.

How do I get rid of vaginal odor?

Find the cause first. Bacterial vaginosis and trichomoniasis need prescription antibiotics. Remove any forgotten tampon. Avoid douching and scented products, wash only the outside with warm water, and wear cotton underwear. Odor that persists or returns should be tested by a clinician.

Is vaginal odor a sign of an STI?

Sometimes. Trichomoniasis, a sexually transmitted infection, commonly causes odor. Chlamydia and gonorrhea usually do not cause odor but can cause abnormal discharge. Bacterial vaginosis, the most common cause, is not considered an STI, though it is linked to sexual activity. Testing tells them apart.

Does a yeast infection cause vaginal odor?

Usually only a mild one, if any. Yeast infections mainly cause itching, burning and thick white discharge. A strong or fishy smell points to bacterial vaginosis or trichomoniasis instead. Using antifungal treatment for an odor problem often does not help, so get tested if unsure.