Metronidazole is the most commonly prescribed antibiotic for bacterial vaginosis (BV), and it cures roughly 80% to 90% of cases when taken as directed. Clindamycin is the main alternative. Both are available as oral pills or vaginal formulations, and the CDC lists them as equally recommended first-line options.
The Two Antibiotics That Treat BV
BV happens when the balance of bacteria in the vagina shifts, with normally dominant lactobacilli replaced by an overgrowth of other bacteria. Antibiotics work by killing off that overgrowth so the healthy bacteria can reestablish themselves. Only two antibiotics are standard treatments:
- Metronidazole: Available as an oral pill (taken twice a day for 7 days) or as a vaginal gel (applied once daily for 5 days).
- Clindamycin: Typically used as a vaginal cream applied at bedtime for 7 days.
Your provider will choose between these based on your symptoms, preferences, and medical history. There is no over-the-counter antibiotic for BV. You need a prescription.
Oral Pills vs. Vaginal Creams and Gels
Both forms work well, so the choice often comes down to convenience and side effects. Oral metronidazole is a simple pill, but it can cause nausea, a metallic taste in your mouth, and digestive upset. The vaginal gel version avoids most of those systemic side effects because less of the drug enters your bloodstream, though some people find the applicator inconvenient or notice local irritation.
Clindamycin cream is only used vaginally for BV. One important detail: oil-based clindamycin cream can weaken latex condoms and diaphragms for up to 5 days after you finish treatment. If you rely on barrier contraception, plan accordingly.
Alcohol and Metronidazole
You’ve probably heard you absolutely cannot drink alcohol while taking metronidazole. The traditional warning is that mixing the two causes severe nausea, vomiting, and flushing. A review in Antimicrobial Agents and Chemotherapy found that this reaction actually “occurs with uncertain frequency and with varied severity,” meaning the risk may be overstated for some people. Still, most providers recommend avoiding alcohol during treatment and for at least 24 to 48 hours after your last dose. It’s a short course of antibiotics, so playing it safe is easy enough.
What to Expect During Treatment
Most people notice improvement within 2 to 3 days of starting antibiotics, but it’s important to finish the full course even if symptoms clear up early. Stopping early increases the chance the bacteria aren’t fully eliminated, which makes recurrence more likely.
Common BV symptoms like thin grayish discharge, fishy odor (especially after sex), and mild irritation should resolve by the time you complete treatment. If symptoms persist after finishing your full course, contact your provider. You may need a different antibiotic or further testing to rule out other infections.
Why BV Keeps Coming Back
Recurrence is the most frustrating part of BV. Up to half of people treated successfully will have another episode within 12 months. The reasons aren’t fully understood, but the overgrowth bacteria can form protective biofilms on vaginal tissue that antibiotics don’t always penetrate completely. Sexual activity also plays a role: research increasingly shows that bacteria associated with BV can be shared between partners.
For people dealing with three or more episodes a year, providers sometimes recommend a longer maintenance approach using vaginal metronidazole gel applied less frequently over several months. This suppressive strategy can reduce the cycle of repeated infections.
Partner Treatment for Recurrent BV
For years, treating sexual partners was not recommended because earlier studies didn’t show a clear benefit. That has changed. In 2025, the American College of Obstetricians and Gynecologists recommended for the first time that male sexual partners of people with recurrent BV be treated with a combination of oral and topical antibiotics. This recommendation followed new research showing that bacteria linked to BV can persist in the male genital tract and reintroduce themselves during sex.
If your BV keeps returning despite completing treatment correctly, ask your provider about concurrent partner therapy. It won’t help everyone, but for recurrent cases tied to sexual transmission, it can break the cycle.
BV vs. Yeast Infections
Many people confuse BV with yeast infections because both cause vaginal discomfort. The key differences: BV typically produces a thin, grayish-white discharge with a noticeable fishy smell, while yeast infections cause thick, white, cottage cheese-like discharge with intense itching but usually no strong odor. This distinction matters because the treatments are completely different. Antifungal medications that treat yeast infections do nothing for BV, and antibiotics for BV won’t help a yeast infection. Getting the right diagnosis before starting treatment saves time and frustration.