The most commonly prescribed antibiotic for bacterial vaginosis (BV) is metronidazole, available as both an oral pill and a vaginal gel. Clindamycin, tinidazole, and secnidazole are also effective options. Which one you’re prescribed depends on your preferences, whether you’re pregnant, and whether BV keeps coming back.
First-Line Options
Metronidazole is the standard starting point for BV treatment. The typical oral regimen is 500 mg taken twice a day for seven days. If you’d rather avoid a pill, metronidazole also comes as a 0.75% vaginal gel applied at bedtime for five days. Both routes work well, and choosing between them is mostly a matter of personal preference and how you respond to the medication.
Clindamycin is the other major first-line option. It’s most commonly used as a 2% vaginal cream applied at bedtime for seven days, though an oral version (300 mg twice daily for seven days) is also available. Some people prefer the vaginal cream because it keeps the medication localized and tends to cause fewer body-wide side effects like nausea.
Alternatives: Tinidazole and Secnidazole
Tinidazole belongs to the same drug class as metronidazole but is noticeably easier on the stomach. In clinical trials, only 6% of people taking tinidazole reported gastrointestinal side effects compared with 41% of those on metronidazole. Nausea, vomiting, and that characteristic metallic taste were all significantly less common with tinidazole. The recommended course for BV is 500 mg twice daily for seven days, though some protocols use a shorter course. Longer treatment courses tend to work better than a single large dose.
Secnidazole is the newest option and stands out because it’s a single 2-gram oral dose, meaning you take one packet of granules mixed into food and you’re done. That convenience makes it appealing if you’ve struggled with completing a full week of twice-daily pills. Clinical trials have shown cure rates above 95% when BV is confirmed by standard diagnostic criteria.
What to Know About Side Effects
The most common complaints with oral metronidazole are nausea, a metallic taste in the mouth, and stomach upset. These are annoying but not dangerous, and they stop once treatment ends. One important rule: you need to avoid alcohol completely while taking metronidazole and for at least three days after your last dose. Metronidazole interferes with how your body breaks down alcohol, causing a buildup of a toxic byproduct called acetaldehyde. The result can be intense nausea, vomiting, flushing, a pounding headache, and a racing heart. The same alcohol restriction applies to tinidazole.
Vaginal formulations of metronidazole and clindamycin sidestep most of those stomach issues. The tradeoff is that clindamycin cream can weaken latex condoms and diaphragms for up to 72 hours after use, so you’d need a backup method during that window.
Treatment During Pregnancy
BV during pregnancy is treated with the same antibiotics, and multiple large trials have confirmed they’re effective at clearing the infection. A Cochrane review covering over 4,300 pregnant women found that antibiotic therapy eliminated BV in the vast majority of cases, with a Peto odds ratio of 0.17 favoring treatment over placebo. Side effects were uncommon and rarely required stopping the medication.
The regimens studied in pregnancy include oral metronidazole (typically 250 mg three times a day for seven days, a slightly lower dose than the standard non-pregnant regimen), oral clindamycin (300 mg twice daily for five days), and 2% clindamycin vaginal cream for seven days. Your provider will choose based on how far along you are and your individual risk factors.
Why BV Comes Back So Often
Recurrence is the single most frustrating thing about BV. Up to 66% of women experience a return of symptoms within a year of their initial treatment. Standard antibiotics clear the overgrown bacteria effectively in the short term, but they don’t always restore the healthy vaginal bacteria (mainly lactobacilli) that keep BV-causing organisms in check.
For people dealing with multiple recurrences, suppressive therapy can help. One approach is using 0.75% metronidazole gel twice a week for three months or longer after completing a full treatment course. This has been shown to reduce recurrences, though the benefit fades once suppressive therapy stops. A more intensive protocol involves a full seven-day course of oral metronidazole or tinidazole, followed by intravaginal boric acid daily for 21 days, then twice-weekly metronidazole gel for four to six months.
Partner Treatment for Recurrent BV
For years, guidelines stated that treating sexual partners wasn’t necessary. That changed in 2025, when the American College of Obstetricians and Gynecologists recommended, for the first time, considering concurrent treatment of male sexual partners when BV keeps recurring. The updated guidance suggests a combination of oral and topical antimicrobial agents for male partners of people with recurrent, symptomatic BV.
For same-sex partners or for a first episode of BV, ACOG recommends shared decision-making, meaning you and your provider weigh the pros and cons together rather than following a blanket rule. This shift reflects growing evidence that BV-associated bacteria can be shared between sexual partners, contributing to the cycle of reinfection that makes recurrence so common.