Proudly Serving CanadiansBacterial Vaginosis (BV): Symptoms, Causes and Treatment
Bacterial vaginosis is the most common cause of unusual vaginal discharge. It happens when the bacteria that normally keep the vagina slightly acidic are crowded out by others, and it is treatable, though it has a stubborn habit of returning.
Get it confirmed firstBV, thrush and trichomoniasis cause overlapping symptoms and need different treatment. Self-diagnosis is wrong often enough to matter, so if this is new to you, ask a doctor, nurse practitioner or pelvic health clinician before you treat it.
Find a pelvic health clinicWhat bacterial vaginosis is
A healthy vagina is mildly acidic. That acidity comes from lactobacilli, bacteria that live there normally and produce lactic acid. The acid is not incidental. It is what makes the environment hostile to other organisms.
In bacterial vaginosis, the lactobacilli population falls and a mix of other bacteria, including Gardnerella vaginalis, grows in their place. Vaginal pH rises above 4.5, and the change in the bacterial mix produces the discharge and odour.
This is the part people most often get wrong: BV is not caused by being unclean. If anything the opposite is true, because washing inside the vagina strips out the lactobacilli that keep the acidity up. It is a shift in a bacterial community, not dirt and not an infection you catch from a toilet seat.
BV is not formally classed as a sexually transmitted infection, but it behaves epidemiologically like one, and a 2025 randomised trial found that treating a regular male partner alongside the patient improved cure rates3. People who have never had sex can still get BV.
Where BV sits on the pH scale
Healthy vaginal pH, 3.8 to 4.5
Is it BV or thrush?
These two get confused constantly, and treating the wrong one wastes time and money. Thrush is a yeast overgrowth and needs an antifungal; BV is a bacterial imbalance and does not respond to antifungals at all. Trichomoniasis is a third possibility and is a true STI. The pattern of discharge, odour and itch usually separates them.
| Sign | Bacterial vaginosis | Thrush (yeast) | Trichomoniasis |
|---|---|---|---|
| Discharge | Thin, grey or white, watery | Thick, white, like cottage cheese | Frothy, yellow-green, heavy |
| Odour | Fishy, stronger after sex | Little or none | Unpleasant, sometimes fishy |
| Itch and soreness | Usually mild or absent | Intense itching, burning | Itching, soreness, pain passing urine |
| Vaginal pH | Above 4.5 | Normal, 4.5 or below | Above 4.5 |
| What treats it | Antibiotics, or a pH-restoring gel for symptoms | Antifungals | Prescription antibiotics, partner treated too |
Up to half of people with BV notice no symptoms at all1. Absence of odour does not rule it out.
Getting it confirmed
A clinician diagnoses BV using the Amsel criteria, and treats when three of the four are present2:
- Thin, white or grey, evenly spread discharge
- Vaginal pH above 4.5
- A positive whiff test, meaning a fishy smell when potassium hydroxide is added to a sample
- Clue cells seen on microscopy of a vaginal swab
Some clinics use a Nugent score instead, which grades a Gram-stained slide, though that is now mostly limited to specialist services2.
Worth knowing: a swab testing for Gardnerella vaginalis alone cannot diagnose BV, because that organism is also found in people who do not have it2. If you are offered a test, it is the combination of findings that matters.
If you have had BV before and recognise the pattern, many clinicians are comfortable treating it without repeating the full workup. If it is the first time, if you are pregnant, or if the symptoms are not behaving the way they did before, get it looked at.
How BV is treated
Prescription antibiotics
Antibiotics are the first-line treatment and are what clear the overgrowth. The regimens recommended by the CDC are metronidazole 500 mg orally twice daily for seven days, metronidazole 0.75% gel vaginally once daily for five days, or clindamycin 2% cream vaginally at bedtime for seven days1. Secnidazole and tinidazole are alternatives.
Finish the full course even once the symptoms settle, which usually happens within a few days. Clindamycin cream weakens latex, so condoms and diaphragms are unreliable during treatment and for 72 hours after1.
Non-antibiotic gels
Lactic acid gels work on the pH rather than the bacteria: they restore the acidity that lets lactobacilli re-establish. They are used to relieve symptoms, after a course of antibiotics to help things settle, and on a repeating schedule by people whose BV keeps returning.
We stock Gynalac, a Health Canada licensed gel (NPN 80077445) of lactic acid and sodium hyaluronate. It is not an antibiotic and does not replace one where antibiotics are needed. If symptoms do not settle, that is the point to go back to your provider.
After a course of antibiotics
Antibiotics clear the overgrowth but do not restore the lactobacilli, which is part of why BV returns so readily. A short course of a pH-restoring gel after treatment is a common way to help that along. For Gynalac that is three days.
Nothing on this page is a substitute for a diagnosis. We sell products that help with BV symptoms and recurrence; we are not able to tell you whether what you have is BV.
When BV keeps coming back
This is the real problem with BV. More than half of people have it again within three to twelve months of treatment, and where there is an untreated regular partner, recurrence runs at 60 to 80%2. That is not a failure on your part.
If you are on your second or third round, it is worth asking your provider about a longer plan rather than repeating a seven-day course each time.
Suppressive treatment
After several recurrences, the CDC describes metronidazole 0.75% gel used twice weekly for more than three months, which reduces recurrence while it is being used, though the benefit does not persist once it stops1.
Boric acid
For repeated recurrences, the CDC notes a sequence of oral metronidazole or tinidazole for seven days, then boric acid 600 mg vaginally daily for 21 days, then metronidazole gel twice weekly for four to six months1. The evidence behind it is limited, and it is a plan to agree with a clinician rather than to start alone.
Boric acid safety. Vaginal use only. Boric acid is poisonous if swallowed and must be kept away from children. Do not use it during pregnancy, or on broken or very irritated tissue.
Treating a partner
This is where guidance is actively changing. A 2025 randomised trial found that treating a regular male partner at the same time improved cure and cut recurrence3, and Australian guidelines now recommend it for people with an ongoing male partner2. The CDC has not adopted routine partner treatment1. If BV keeps returning and you have a regular partner, it is a reasonable thing to raise.
What does not help
- DouchingIt makes BV more likely rather than less, by washing out the lactobacilli that keep the vagina acidic. No evidence supports it for treating BV or relieving symptoms, and it may raise the risk of relapse1.
- Scented washes, wipes and deodorantsSame mechanism. The vagina is self-cleaning; washing the vulva with plain water or a mild unscented cleanser is enough.
- Oral probiotics, on current evidenceThis one is worth being straight about. The CDC's position is that no studies support probiotic products as either an addition to or a replacement for BV treatment1. One specific vaginal strain, L. crispatus CTV-05, did reduce recurrence in a trial, but it is not commercially available. People do take probiotics for general vaginal health, and that is a reasonable thing to do, just not as a treatment for an active case of BV.
- High-dose vitamin DTrials did not show it reduces recurrence, and the CDC does not recommend it1.
- Treating it as thrushAntifungals do nothing for BV. If an over-the-counter thrush treatment has not worked, that is a reason to get the diagnosis checked rather than to try a stronger one.
BV in pregnancy
Symptomatic BV in pregnancy should be treated, because it is associated with preterm birth and premature rupture of membranes1. Oral metronidazole is used, and clindamycin is an option; tinidazole and secnidazole are avoided1.
Routine screening of pregnant people without symptoms is not recommended, and treating asymptomatic BV has not been shown to help in low-risk pregnancies1.
If you are pregnant and have symptoms, speak to your midwife or doctor rather than treating it yourself. Boric acid in particular should not be used in pregnancy.
What we stock for BV
These support treatment and help with recurrence. None of them diagnoses BV, and none replaces antibiotics where antibiotics are needed.
Gynalac® Vaginal GelNon-antibiotic lactic acid and hyaluronate gel that restores vaginal pH. Used for seven days to relieve symptoms, for three days after a course of antibiotics, or monthly after a period to help prevent recurrence. Health Canada licensed, NPN 80077445.View
Boric Balance Suppositories600 mg boric acid suppositories, as used in the recurrent-BV sequence described above. Vaginal use only, never swallowed, not in pregnancy. Best used as part of a plan agreed with your provider.View
Vaginal Suppository ApplicatorsReusable applicators for inserting suppositories cleanly and to a consistent depth.View
Women's health supplements and productsThe wider range, including probiotics and vaginal moisturisers.Browse
Common questions
Can BV go away on its own?
Sometimes it does. But it can also persist, and untreated BV is associated with a higher risk of acquiring other infections, so it is better to have symptoms looked at than to wait it out.
Is BV a sexually transmitted infection?
It is not formally classed as one, and people who have never had sex can get it. That said, it has the epidemiological profile of an STI, new or multiple partners raise the risk, and a 2025 trial showed treating a regular male partner improves cure.
Why does my BV keep coming back?
Recurrence is the norm rather than the exception. More than half of people have it again within three to twelve months. Antibiotics clear the overgrowth but do not restore the lactobacilli, and an untreated regular partner pushes recurrence as high as 60 to 80%. If it keeps returning, ask about a longer suppressive plan.
Can I treat BV without antibiotics?
A pH-restoring gel can relieve symptoms and help prevent recurrence, and some mild cases settle that way. It is not a replacement for antibiotics where they are needed. If symptoms do not improve, or you are pregnant, see your provider.
Should I use a probiotic?
Current guidance does not support probiotics as a treatment for an active case. Plenty of people take them for general vaginal health, which is a different thing, and is reasonable.
Can my partner catch it?
Partners with a vagina can be affected and should be offered testing. For partners with a penis, treating them at the same time is now recommended in some guidelines where the relationship is ongoing, though not yet by the CDC.
Is it safe to have sex while being treated?
There is no rule against it, but clindamycin cream weakens latex for up to 72 hours, so condoms and diaphragms are unreliable during that time. If a partner is being treated alongside you, guidelines advise avoiding unprotected sex until you have both finished.
References
-
Centers for Disease Control and Prevention. Bacterial Vaginosis. Sexually Transmitted Infections Treatment Guidelines.
Read the guideline -
Australasian Sexual and Reproductive Health Alliance. Bacterial vaginosis. Australian STI Management Guidelines for Use in Primary Care.
Read the guideline -
Vodstrcil LA, et al. Male-Partner Treatment to Prevent Recurrence of Bacterial Vaginosis. New England Journal of Medicine, 2025.
View on PubMed
This page is for information and does not replace advice from a doctor, nurse practitioner or pelvic health clinician. If your symptoms are new, severe, do not settle with treatment, or you are pregnant, please speak to a healthcare professional. You can find a clinic near you using our directory.
