BV Treatment With Metronidazole: Pills vs Gel, Side Effects and Alcohol

Written by Naurah Gaspard, DNP, FNP-C, FNP-BC · Medically reviewed by Cherlie Joseph, MSN, FNP-BC · Updated November 2026

Metronidazole is the most common treatment for bacterial vaginosis (BV). It comes as a 7-day course of pills taken twice a day or a vaginal gel used once a day for 5 days, and both work about equally well. Clindamycin cream or pills and single-dose secnidazole are other prescription options, and new 2025 guidance now supports treating male partners when BV keeps coming back.

What BV is and why it needs treatment

Bacterial vaginosis happens when the protective Lactobacillus bacteria in the vagina drop and other bacteria overgrow. It is the most common cause of abnormal vaginal discharge in women of reproductive age. Typical signs are thin gray or white discharge and a fishy odor that is often stronger after sex or during a period. Unlike a yeast infection, BV usually causes little itching.

The CDC recommends treating BV whenever it causes symptoms. Treatment relieves odor and discharge and lowers the risk of picking up other infections, including chlamydia, gonorrhea and HIV. BV is not treated with antifungals, so over-the-counter yeast creams will not help.

Metronidazole pills vs gel vs other options

These are the regimens listed in the CDC STI Treatment Guidelines. Your provider chooses based on your history, preferences and whether you are pregnant.

Treatment	How it is used	Good to know
Metronidazole pills (Flagyl)	By mouth twice daily for 7 days	First-line; inexpensive generic; can cause metallic taste or nausea
Metronidazole 0.75% gel	One applicator in the vagina once daily for 5 days	Fewer stomach side effects; some leakage
Clindamycin 2% cream	One applicator at bedtime for 7 days	Oil-based; can weaken latex condoms and diaphragms for 5 days after use
Secnidazole (Solosec)	Single dose of granules mixed into soft food	One and done, but usually costs more; not used in pregnancy
Tinidazole or clindamycin pills	Short oral courses	Alternatives; tinidazole is avoided in pregnancy

During pregnancy, BV with symptoms should be treated, and metronidazole is considered low risk according to the CDC.

Side effects and tips for finishing treatment

Common metronidazole side effects include a metallic taste, nausea, stomach upset, headache and darker urine. The gel causes fewer stomach symptoms but can cause vaginal irritation or discharge. Rarely, metronidazole causes numbness or tingling in the hands or feet, seizures, or severe skin reactions; stop and get care right away if those happen.

• Finish the full course, even if the odor clears in a day or two.
• Take pills with food if they upset your stomach.
• Avoid sex or use condoms during treatment, as the CDC advises.
• Watch for a yeast infection afterward. Itching after BV treatment is common and is treated separately.

Metronidazole and alcohol

For decades, people were told never to drink on metronidazole because of a possible reaction with flushing, nausea, vomiting and a fast heartbeat. The FDA drug label still advises avoiding alcohol during treatment and for at least 3 days after the last dose.

In its 2021 guidelines, however, the CDC said studies have not shown convincing evidence of this reaction and that avoiding alcohol is not required. Because the label and the guidelines differ, the safest plan is to follow your prescriber's advice. Many providers still recommend skipping alcohol until a few days after you finish, which also helps with nausea.

When BV keeps coming back

BV often returns within months of treatment. Options for recurrent BV include:

• Repeating the same treatment after a first recurrence.
• Suppressive therapy: after a full treatment course, metronidazole gel used twice a week for more than 3 months has reduced recurrences, though BV can return when it stops.
• Boric acid vaginal capsules combined with metronidazole for some people with repeated recurrences, under a provider's guidance. Boric acid is poisonous if swallowed.
• Treating male partners. In a 2025 New England Journal of Medicine trial of 164 couples, BV came back within 12 weeks in 35% of women whose male partners were also treated, compared with 63% when only the woman was treated. In October 2025, ACOG began recommending treating male partners at the same time for recurrent BV. Older CDC guidance from 2021 did not recommend routine partner treatment, so ask your provider what fits your situation.

Frequently asked questions

How fast does metronidazole work for BV?

Many people notice less odor and discharge within 2 to 3 days, but you need to finish the full course to clear the infection and lower the chance it comes back.

Can I drink alcohol while taking metronidazole for BV?

The FDA label advises avoiding alcohol during treatment and for 3 days after. The CDC says evidence for a serious reaction is weak. Follow your prescriber's advice; many still recommend avoiding it.

Does my partner need treatment for BV?

For a single BV episode, partners usually are not treated. For BV that keeps coming back, ACOG now recommends treating male partners at the same time, based on a 2025 trial that showed fewer recurrences.

Sources

• CDC: Bacterial Vaginosis, STI Treatment Guidelines
• Vodstrcil LA, et al. Male-Partner Treatment to Prevent Recurrence of Bacterial Vaginosis. N Engl J Med. 2025

Keep reading

• Yeast infection vs BV: how to tell the difference
• STD testing online in Florida
• Yeast infection after antibiotics
• Browse all conditions and treatments A to Z

This article is for general education and is not a substitute for medical advice. Treatment, including any prescription, is decided by a licensed provider after reviewing your health history. OurTopClinic is not for emergencies; if you have a medical emergency, call 911. OurTopClinic serves adults located in Florida, New Mexico, Oregon and Washington. Learn more at ourtopclinic.com.