Bacterial vaginosis (BV) is treated with prescription antibiotics, and most cases clear up within a week. The most common option is a 7-day course of oral metronidazole, though vaginal gels and creams work just as well. The harder part is keeping it from coming back, which happens in roughly half of cases within 12 months. Here’s what actually works, what doesn’t, and what to do if BV keeps returning.
What BV Is and Why It Happens
BV isn’t a traditional infection caused by a single invading germ. It’s a shift in the balance of bacteria that naturally live in the vagina. Normally, beneficial bacteria (mainly Lactobacillus species) dominate and keep the environment slightly acidic, with a healthy pH between 3.8 and 4.5. When those protective bacteria get crowded out by other organisms, the pH rises and symptoms appear: a thin grayish-white discharge, a fishy odor (often stronger after sex), and sometimes mild irritation.
Several things can trigger this shift. Douching is one of the most consistent risk factors because it flushes out protective bacteria and disrupts acidity. Sexual activity plays a role too. Semen is alkaline, which temporarily raises vaginal pH, and new or multiple partners increase the likelihood of introducing bacteria that tip the balance. Scented soaps, bubble baths, and fragranced hygiene products can also irritate vaginal tissue and alter pH. Hormonal changes during menstruation or pregnancy matter as well.
Prescription Treatments That Work
The CDC recommends three first-line options, all with similar cure rates:
- Oral metronidazole: taken twice a day for 7 days. This is the most widely prescribed option.
- Metronidazole vaginal gel (0.75%): applied once a day for 5 days. This puts the medication directly where it’s needed and causes fewer side effects like nausea.
- Clindamycin vaginal cream (2%): applied at bedtime for 7 days. A good alternative if you can’t tolerate metronidazole.
If those don’t work or aren’t an option, your provider may prescribe tinidazole, which is taken orally for 2 to 5 days depending on the dose. A newer single-dose option, secnidazole (one 2-gram dose taken just once), has shown cure rates comparable to the full 7-day metronidazole course. A meta-analysis found no significant difference between the two, making it a convenient choice if you want to skip the week of pills.
Oral metronidazole can cause nausea and a metallic taste, and you need to avoid alcohol during treatment and for at least 24 hours after finishing. The vaginal formulations generally have fewer of these systemic side effects. Most people notice symptoms improving within 2 to 3 days, but it’s important to finish the full course even if you feel better.
Why BV Keeps Coming Back
Recurrence is the most frustrating part of BV. The bacteria that cause it can form a sticky, protective layer called a biofilm on vaginal tissue. Antibiotics kill the free-floating bacteria but often can’t fully penetrate this biofilm, so the problematic organisms bounce back after treatment ends.
Sexual transmission also plays a bigger role than previously thought. For years, guidelines didn’t recommend treating male partners. That changed in 2025 when the American College of Obstetricians and Gynecologists recommended, for the first time, considering concurrent treatment for male sexual partners of people with recurrent BV. The recommendation followed growing evidence that BV-associated bacteria can persist on penile skin and be reintroduced during sex, essentially reinfecting a partner who just finished treatment. If you’re dealing with recurring BV, this is worth discussing with your provider.
Boric Acid for Stubborn Cases
Boric acid vaginal suppositories (600 mg) are sometimes used alongside or after antibiotics, particularly for recurrent BV. They work by lowering vaginal pH back into the acidic range where Lactobacillus thrives, making the environment inhospitable to BV-associated bacteria. Clinical studies show that the 600 mg suppositories act primarily locally, with only about 6% absorbed into the bloodstream, which limits systemic side effects.
Boric acid is not a standalone cure for an active BV episode. It’s most useful as a follow-up strategy after a course of antibiotics, helping maintain the acidic environment and reduce the chance of recurrence. It should never be taken orally (it’s toxic when swallowed) and should not be used during pregnancy.
What About Probiotics?
The idea of replenishing “good” bacteria with probiotics is appealing, but the evidence is mixed. A randomized controlled trial testing two of the most widely marketed probiotic strains (L. rhamnosus GR-1 and L. reuteri RC-14) found no improvement in cure rates when added to standard metronidazole treatment. The 30-day cure rate was virtually identical: about 58% in the probiotic group versus 60% with metronidazole alone. At 90 days, the probiotic group actually trended slightly worse. One likely reason: the probiotic species were rarely detected in either vaginal or stool samples after oral administration, meaning they simply weren’t colonizing where they needed to.
One strain that does show promise is L. crispatus CTV-05 (sold under the name Lactin-V), which is applied vaginally rather than taken by mouth. A phase IIb trial found it significantly reduced BV recurrence when used after metronidazole treatment compared to placebo. The key difference is route of delivery. Vaginal probiotics have a better chance of actually establishing themselves in the vaginal ecosystem than oral capsules that have to survive the entire digestive tract first.
Home Remedies to Avoid
Tea tree oil and apple cider vinegar are commonly suggested online, but neither has good evidence behind it. Tea tree oil can cause allergic reactions and tissue irritation, and it is not safe during pregnancy. No studies have examined the direct effects of apple cider vinegar on BV. Applying undiluted vinegar to already-irritated vaginal tissue risks chemical burns and worsening inflammation.
Douching with any substance, including hydrogen peroxide or yogurt, tends to make BV worse by further disrupting the bacterial ecosystem. The vagina is self-cleaning. Warm water on the external vulva is all you need for daily hygiene.
Preventing Recurrence
There’s no guaranteed way to prevent BV, but several habits reduce the odds of disrupting your vaginal balance:
- Skip douching entirely. This is the single most actionable prevention step.
- Use unscented products. Choose fragrance-free soap, laundry detergent, and menstrual products. Scented tampons and pads sit directly against vaginal tissue for hours.
- Use condoms. They reduce exposure to semen (which raises pH) and limit exchange of bacteria between partners.
- Change out of wet clothing promptly. Damp swimsuits and workout gear create a warm, moist environment that favors bacterial overgrowth.
- Consider post-antibiotic maintenance. For people with frequent recurrence, some providers prescribe twice-weekly vaginal metronidazole gel for several months after the initial treatment course to suppress regrowth.
If you’re getting BV three or more times in a year, bring up partner treatment and suppressive therapy with your provider. The combination of a full antibiotic course, concurrent partner treatment, and a maintenance strategy afterward gives the best chance of breaking the cycle for good.