Gardnerella vaginalis is treated with prescription antibiotics, either taken by mouth or applied vaginally. This bacterium is the primary driver of bacterial vaginosis (BV), a condition where the normal balance of vaginal bacteria shifts, allowing Gardnerella and other organisms to overgrow. Treatment typically clears symptoms within a week, though recurrence is common and sometimes requires a longer-term strategy.
What Gardnerella Vaginalis Actually Is
Gardnerella vaginalis isn’t a sexually transmitted infection in the traditional sense, but it’s closely tied to sexual activity. In a healthy vagina, beneficial Lactobacillus bacteria keep the environment acidic, which suppresses harmful organisms. When that balance tips, Gardnerella multiplies and forms a sticky biofilm on the vaginal wall. This biofilm is a major reason BV tends to come back: antibiotics kill the free-floating bacteria but often can’t fully penetrate the protective layer Gardnerella builds around itself.
The hallmark symptoms are a thin, grayish-white discharge and a fishy odor that’s often stronger after sex. Some people also experience mild itching or burning during urination. About half of those with BV have no symptoms at all, which is why it sometimes shows up unexpectedly on a routine test.
First-Line Antibiotic Options
The CDC recommends three equally effective first-line treatments:
- Oral metronidazole: 500 mg taken twice daily for 7 days
- Vaginal metronidazole gel (0.75%): one applicator inserted daily for 5 days
- Vaginal clindamycin cream (2%): one applicator inserted at bedtime for 7 days
The oral and vaginal routes work about equally well for a first episode. Some people prefer the vaginal options because they cause fewer digestive side effects like nausea. Others prefer a pill for convenience. Your provider can help you choose based on your preferences and medical history.
One important caution with metronidazole: avoid alcohol completely while taking it and for two full days after finishing. The combination can cause severe nausea, vomiting, and flushing. This applies to both the oral tablets and vaginal gel.
Why BV Keeps Coming Back
Recurrence is the biggest frustration with BV treatment. Roughly half of people who are successfully treated will have another episode within 12 months. Several factors drive this pattern. The Gardnerella biofilm can survive a standard antibiotic course and regrow once treatment stops. Sexual contact can reintroduce the bacteria, and shifts in vaginal pH from menstruation, new partners, or douching can trigger another flare.
For recurrent BV (generally defined as three or more confirmed episodes in a year), providers often prescribe a longer suppressive regimen. This typically involves completing a standard treatment course and then continuing with a lower maintenance dose of vaginal metronidazole gel, applied once or twice per week for several months. The goal is to keep Gardnerella suppressed long enough for beneficial bacteria to reestablish themselves.
Partner Treatment: A Shifting Recommendation
For years, treating sexual partners wasn’t recommended because the evidence was inconclusive. That changed in 2025 when the American College of Obstetricians and Gynecologists (ACOG) recommended concurrent partner treatment for recurrent BV for the first time. A growing body of evidence now implicates sexual transmission as a significant factor in reinfection, particularly with male partners who can harbor Gardnerella without symptoms.
This recommendation is still evolving. More research is needed for people with same-sex partners, those in nonmonogamous relationships, and people with asymptomatic BV. But if you’ve been dealing with repeated episodes, asking your provider about partner treatment is now a reasonable conversation to have.
The Role of Boric Acid
Boric acid vaginal suppositories have gained attention as an add-on treatment, particularly for stubborn or recurrent cases. They’re not a replacement for antibiotics, but they appear to help by breaking down the bacterial mucus layer that protects Gardnerella’s biofilm. This can make antibiotics more effective at reaching the bacteria underneath.
The typical dose is 600 mg inserted vaginally once daily for 7 to 14 days, often used alongside or immediately after an antibiotic course. Boric acid is available over the counter, but it should only be used vaginally, never taken by mouth (it’s toxic if swallowed), and it should not be used during pregnancy.
Probiotics and Rebuilding Vaginal Flora
Restoring healthy Lactobacillus bacteria after antibiotics is an active area of treatment research. One specific product, LACTIN-V, contains a strain called Lactobacillus crispatus CTV-05, which is the same species that dominates a healthy vaginal microbiome. In a randomized trial, women who used this probiotic vaginally for 11 weeks after antibiotic treatment had significantly lower recurrence rates: 30% experienced a recurrence by 12 weeks compared to 45% in the placebo group. By 24 weeks, the gap held at 39% versus 54%.
The probiotic also tripled the likelihood of achieving a Lactobacillus-dominant vaginal microbiome by week 12 (30% of recipients versus 9% on placebo). These numbers are encouraging but also honest about the challenge: even with probiotic support, recurrence is still common. LACTIN-V is not yet widely available, but the research supports the broader principle that restoring protective bacteria matters for long-term prevention.
Over-the-counter vaginal probiotics are widely sold, though most haven’t been tested as rigorously. If you want to try one, look for products containing Lactobacillus crispatus or Lactobacillus rhamnosus, which have the most supporting evidence. Oral probiotics are less likely to colonize the vagina effectively than vaginal formulations.
Treatment During Pregnancy
BV during pregnancy is associated with an increased risk of preterm birth and other complications, so treatment is recommended even when symptoms are mild. The same antibiotic regimens used for non-pregnant individuals apply, with oral metronidazole being the most commonly prescribed option. Vaginal clindamycin and metronidazole gel are also considered safe. Boric acid, however, should not be used during pregnancy.
Habits That Support Recovery
Antibiotics do the heavy lifting, but a few practical steps can improve your chances of staying clear after treatment. Avoid douching entirely. It disrupts the vaginal pH and washes away protective bacteria. Use unscented soap only on the external vulva, and skip internal cleaning products. Condoms reduce the risk of BV recurrence by limiting the exchange of bacteria during sex.
Menstrual blood is alkaline, which temporarily raises vaginal pH each month and can trigger a flare. If you notice a pattern of BV returning around your period, that’s worth mentioning to your provider, as it may influence the timing of a maintenance regimen. Smoking is also a well-established risk factor for BV, likely because it reduces the vaginal immune response. Quitting meaningfully lowers recurrence risk.