A vaginal bacterial infection, most commonly called bacterial vaginosis (BV), is treated with prescription antibiotics that typically clear symptoms within five to seven days. It’s the most common vaginal infection in women of reproductive age, and while it often resolves fully with a first round of treatment, recurrence is extremely common: 50% to 80% of women will have another episode within 6 to 12 months.
What’s Actually Happening in Your Body
Your vagina naturally contains a mix of bacteria, with protective species called lactobacilli making up the majority. These bacteria produce hydrogen peroxide and lactic acid, which keep the vaginal environment slightly acidic and prevent harmful organisms from multiplying. BV happens when something disrupts this balance, causing the protective bacteria to drop sharply while other types of bacteria overgrow and take over.
That overgrowth raises your vaginal pH, making the environment more alkaline. The new dominant bacteria break down proteins and produce amine compounds, which is what causes the characteristic fishy smell. The exact trigger that starts this chain reaction isn’t fully understood, but the result is always the same: a shift from a healthy, lactobacillus-dominated environment to one overrun by anaerobic bacteria.
BV vs. a Yeast Infection
Many people confuse BV with a yeast infection because both cause abnormal discharge, but the two look and feel quite different. BV produces thin, grayish discharge that’s heavy in volume and has a noticeable fishy odor, especially after your period or after sex. It can cause mild irritation but typically isn’t painful.
A yeast infection, by contrast, produces thick, white, cottage cheese-like discharge with little to no odor. Itching and burning are the main symptoms, and intercourse is often painful. This distinction matters because the treatments are completely different. Over-the-counter antifungal creams treat yeast infections but do nothing for BV, which requires prescription antibiotics.
Prescription Treatments That Work
The CDC recommends three first-line options for BV, all equally effective:
- Oral metronidazole: taken twice a day for 7 days
- Metronidazole vaginal gel: applied once a day for 5 days
- Clindamycin vaginal cream: applied at bedtime for 7 days
If those don’t work well for you or you’ve had side effects in the past, alternative options include oral clindamycin for 7 days, clindamycin vaginal ovules for 3 days, or a single-dose oral granule medication called secnidazole. Your provider will choose based on your history, preferences, and whether you’ve dealt with BV before. The oral pill is convenient, but vaginal options tend to cause fewer digestive side effects like nausea.
Most women notice improvement within two to three days of starting treatment, but finishing the full course matters. Stopping early because symptoms feel better is one of the most common reasons BV comes back quickly.
Why BV Keeps Coming Back
Recurrence is the single most frustrating thing about BV. Up to 66% of women experience another episode within a year of treatment. The antibiotics kill the overgrown bacteria, but they don’t always allow the protective lactobacilli to fully re-establish themselves, leaving you vulnerable to another disruption.
Sexual activity plays a bigger role in recurrence than previously thought. For years, treating male sexual partners wasn’t recommended because the evidence was mixed. That changed in 2025, when the American College of Obstetricians and Gynecologists recommended for the first time that male partners of women with recurrent BV be treated with a combination of oral and topical antibiotics. The reasoning: BV-associated bacteria can live on the penis and reintroduce themselves during sex, essentially reinfecting you after each round of treatment. If you’re dealing with repeat infections and have a regular male partner, this is worth discussing with your provider.
Probiotics and Supportive Approaches
Probiotics containing specific lactobacillus strains show genuine promise for BV, though they work best alongside standard treatment rather than replacing it. In one clinical trial, vaginal probiotic suppositories resolved BV in 85% to 88% of women, compared to 45% to 50% of those treated with metronidazole gel alone. Oral probiotics containing Lactobacillus rhamnosus GR-1 and a related strain have also been shown to increase vaginal lactobacilli and reduce harmful bacteria over a 60-day period.
Not all probiotic products are equal. Most over-the-counter options contain strains that were never tested for vaginal health. Look for products that specifically list strains studied for BV, and consider vaginal formulations over oral ones for more direct delivery. Probiotics are not a guaranteed fix, but for women dealing with recurrent BV, adding them after antibiotic treatment can help the protective bacteria re-establish faster.
Reducing Your Risk
The single most impactful thing you can do to prevent BV is stop douching. Women who douche at least once a month have a 1.4 times higher risk of developing BV, and those who douched within the past week have 2.1 times the risk. Douching strips away the hydrogen peroxide and lactobacilli that protect the vaginal environment, essentially creating the exact conditions BV needs to develop. Your vagina is self-cleaning. Warm water on the outside is all you need.
Other practical steps that support a healthy vaginal microbiome:
- Avoid scented products near the vulva and vagina, including scented tampons, sprays, and bubble baths
- Wear breathable underwear made from cotton, and change out of wet swimsuits or sweaty workout clothes promptly
- Use condoms consistently with new or casual partners, since semen is alkaline and raises vaginal pH temporarily
- Wipe front to back to avoid introducing rectal bacteria into the vaginal area
None of these habits will cure an active infection, but they reduce the frequency of recurrences by keeping your vaginal environment stable. For women stuck in a cycle of repeated BV episodes, combining a full antibiotic course with partner treatment, probiotics, and consistent prevention habits offers the best shot at breaking the pattern.