Bacterial Vaginosis (BV)

Last Updated October 2023 | This article was created by editorial staff and reviewed by Kyle Bradford Jones, MD, FAAFP

What is bacterial vaginosis?

Bacterial vaginosis is a mild infection in the vagina caused by a type of bacteria (germ). The vagina normally contains a lot of “good” bacteria, called lactobacilli. It also contains a few other types of bacteria, called anaerobes. Too many anaerobes can cause bacterial vaginosis. It is not known why the anaerobe bacteria overgrow and cause this infection.

Symptoms of bacterial vaginosis

You may notice a discharge from your vagina. The discharge may be clear or colored. It may be very light or heavy. It may have a fishy smell. This smell may be more intense after you have sexual intercourse. Some women have bacterial vaginosis without any symptoms.

What causes bacterial vaginosis?

BV is an overgrowth of bacteria that are normally in the vagina. Researchers do not completely understand why it occurs. However, activities such as douching can put you at greater risk for bacterial vaginosis. So can having a new sexual partner or multiple sexual partners—even though it is not a sexually transmitted infection. BV is more common in women who are sexually active. But it also occurs in women who are not sexually active. It’s not usually necessary for your sex partner to be treated if they come in contact with you.

How is bacterial vaginosis diagnosed?

Your doctor will examine your vagina and use a cotton swab to get a sample of the discharge. This sample will be tested to see if you have too much anaerobe bacteria.

Can bacterial vaginosis be prevented or avoided?

You may not be able to prevent BV. Your doctor may recommend using things like probiotics. You’ll either take these by mouth or by placing them in your vagina. Other ways to reduce your risk:

  • Use condoms. Condoms can help prevent the spread of BV.
  • Keep sex toys clean. Do not share sex toys with other people. Always clean them after use.
  • Limit your number of sexual partners. Monogamy (having sex with only one partner) is the one of the best ways to prevent BV.
  • Do not douche. This can cause an imbalance in vaginal bacteria.
  • See your doctor. If you feel you have symptoms of BV, tell your doctor.

Bacterial vaginosis treatment

BV can be treated in one of several ways. Your doctor may prescribe pills for you to take by mouth. They may also prescribe a cream or gel to put in your vagina. It’s important to use your medicine exactly as your doctor tells you.

If your doctor prescribes metronidazole or other medicines, don’t drink any alcohol while taking the medicine. You should not drink alcohol for 24 hours after taking metronidazole. Combining alcohol with these medicines can cause nausea and vomiting. Even the small amount of alcohol in many cough syrups can cause nausea and vomiting if you’re taking metronidazole. Be sure to tell your doctor about any other medicines you are currently taking.

If the infection isn’t treated, the bacteria may spread into the uterus or the fallopian tubes and cause more serious infections. Treating BV lowers this risk. Treatment is especially important in pregnant women.

Living with bacterial vaginosis

Some women suffer from chronic (recurring) BV. Medicine can clear up the infection, but it returns again after a few weeks. Some women report that BV returns after their period each month. Or it can return after they have sex. Talk to your doctor if you have chronic BV. Your doctor may suggest certain lifestyle changes that can help, like taking probiotics.

Questions to ask your doctor

  • What is the likely cause of my bacterial vaginosis?
  • Do I need any tests, such as for sexually transmitted infections?
  • What do my test results mean?
  • What treatment option do you recommend?
  • Will I need medicine? How do I take it?
  • When can I expect relief from my symptoms?
  • Is it safe for me to have sex?


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