Bacterial vaginosis


Bacterial vaginosis (BV) can cause discomfort and pain of the vagina. It happens when natural bacteria levels are out of balance. Balanced levels of bacteria help keep the vagina healthy. But when too much of some bacteria grow, it can lead to BV.

Bacterial vaginosis can happen at any age. But it's most common during the reproductive years. The changes in hormones during this time make it easier for certain kinds of bacteria to grow. Also, bacterial vaginosis is more common among those who are sexually active. It's not clear why this is. But activities such as unprotected sex and douching raise your risk of having BV.


Symptoms of bacterial vaginosis include:

  • Thin, vaginal discharge that may be gray, white or green.
  • Foul-smelling, "fishy" vaginal odor.
  • Vaginal itching.
  • Burning during urination.

Many people with bacterial vaginosis have no symptoms.

When to see a doctor

Make an appointment to see a health care professional if:

  • Your vaginal discharge smells unusual and you have discomfort. Your doctor can help find the cause of your symptoms.
  • You've had vaginal infections before but your discharge seems different this time.
  • You have a new sex partner or different sex partners. Sometimes, the symptoms of a sexually transmitted infection (STI) are the same as those of bacterial vaginosis.
  • You thought you had a yeast infection but still have symptoms after self-treatment.


Bacterial vaginosis happens when the vagina's natural bacteria levels are out of balance. The bacteria in the vagina are called the vaginal flora. Balanced vaginal flora help keep the vagina healthy. Usually "good" bacteria outnumber "bad" bacteria. The good bacteria are called lactobacilli; the bad bacteria are anaerobes. When there are too many anaerobes, they upset the balance of the flora, causing bacterial vaginosis.

Risk factors

Risk factors for bacterial vaginosis include:

  • Having different sex partners or a new sex partner. The link between having sex and bacterial vaginosis isn't clear. But BV happens more often when someone has different or new sex partners. Also, BV is more common when the sex of both partners is female.
  • Douching. The vagina is self-cleaning. So rinsing your vagina with water or something else isn't needed. It may even cause problems. Douching upsets the vagina's healthy balance of bacteria. It can lead to an overgrowth of anaerobic bacteria, causing bacterial vaginosis.
  • Natural lack of lactobacilli bacteria. If your vagina doesn't produce enough lactobacilli, you're more likely to develop bacterial vaginosis.


Bacterial vaginosis doesn't cause complications very often. But sometimes, having BV may lead to:

  • Sexually transmitted infections. If you have BV, you have a higher risk of getting an STI. STIs include HIV, herpes simplex virus, chlamydia or gonorrhea. If you have HIV, bacterial vaginosis raises the risk of passing the virus to your partner.
  • Infection risk after gynecological surgery. Having BV may increase the risk of developing an infection after surgery such as hysterectomy or dilation and curettage (D&C).
  • Pelvic inflammatory disease (PID). Bacterial vaginosis can sometimes cause PID. This infection of the uterus and the fallopian tubes raises the risk of infertility.
  • Pregnancy issues. Past studies have shown a possible link between BV and problems with pregnancy. These include preterm birth and low birth weight. New studies show that these risks may be due to other reasons. These reasons include having a history of early delivery. But the studies agree that you should be tested if you notice symptoms of BV while pregnant. If positive, your doctor can choose the best treatment for you.


To help prevent bacterial vaginosis:

  • Don't use scented products. Wash your genitals with warm water only. Scented soaps and other scented products may inflame vaginal tissues. Use unscented tampons or pads only.
  • Don't douche. Douching won't clear up a vaginal infection. It may even make it worse. Your vagina doesn't require cleansing other than normal bathing. Douching disrupts the vaginal flora, raising your risk of infection.
  • Practice safe sex. To lower your risk of STIs, use latex condoms or dental dams. Clean any sex toys. Limit your number of sex partners or don't have sex.


To diagnose bacterial vaginosis, your doctor may:

  • Ask questions about your medical history. Your doctor may ask about any vaginal infections or STIs you've had before.
  • Perform a pelvic exam. First, your doctor will look at your vagina for signs of infection. Next, the doctor will feel your pelvic organs. This is done by inserting two fingers into the vagina while pressing on the stomach area, also called the abdomen, with the other hand.
  • Take a sample of vaginal discharge. This sample will be tested for "clue cells." Clue cells are vaginal cells covered in bacteria. These are a sign of BV.
  • Test your vaginal pH. The acidity of your vagina can be tested with a pH strip. You place the test strip in your vagina. A vaginal pH of 4.5 or higher is a sign of bacterial vaginosis.
How a pelvic exam is done


To treat bacterial vaginosis, your doctor may prescribe one of the following medicines:

  • Metronidazole (Flagyl, Metrogel-Vaginal, others). This medicine comes as a pill or topical gel. You swallow the pill, but the gel is inserted into your vagina. Avoid alcohol while using this medicine and for a full day afterward. It might cause nausea or stomach pain. Check the instructions on the product.
  • Clindamycin (Cleocin, Clindesse, others). This medicine comes as a cream that you insert into the vagina. Or you can use the pill or suppository form. The cream and suppositories may weaken latex condoms. Avoid sex during treatment and for at least three days after you stop using the medicine. Or use another method of birth control.
  • Tinidazole (Tindamax). You take this medicine by mouth. It can cause stomach upset. So avoid alcohol during treatment and for at least three days after completing treatment.
  • Secnidazole (Solosec). This is an antibiotic you eat one time with food. It comes as a packet of granules that you sprinkle onto a soft food, such as applesauce, pudding or yogurt. You eat the mixture within 30 minutes. But take care not to crunch or chew the granules.

Usually, treatment isn't needed for a sex partner whose sex is male. But BV can spread to partners whose sex is female. So testing and treatment may be needed if a female partner has symptoms.

Take your medicine or use the cream or gel for as long as prescribed, even if your symptoms go away. If you stop treatment early, BV may come back. This is called recurrent bacterial vaginosis.


It's common for bacterial vaginosis to come back within 3 to 12 months even with proper treatment. Researchers are exploring options for recurrent BV. If your symptoms return soon after treatment, talk with your care team. It might be possible for you to take extended-use metronidazole therapy.

There may be some benefit to probiotics, but more information is needed. In a random trial, probiotics were no better than a treatment that didn't contain medicine, called a placebo, in stopping recurrent BV. So probiotics are not recommended as a treatment option for bacterial vaginosis.

Preparing for an appointment

Try to schedule your appointment on a day when you don't have your period. Bleeding from a period may stop your doctor from seeing your vaginal discharge clearly. For 24 hours before your appointment, don't use tampons or vaginal sprays and don't douche or have sex.

What you can do

Here are some tips to make the best use of time with your provider:

  • List your symptoms. Include all of them. Even if you don't think they're related.
  • List your medicines and supplements. This includes vitamins and herbs. State how often you take them and how much you take.
  • Take notes. Bring a notepad or device with you to track important information during your visit.
  • Have questions ready. List your most important questions first.

For bacterial vaginosis, some basic questions to ask include:

  • Can I do anything to prevent bacterial vaginosis?
  • What symptoms should I look for?
  • Do I need to take medicine?
  • Should my partner be tested or treated?
  • Are there any special instructions for taking the medicine?
  • Are there any products that I can buy without a prescription to treat my condition?
  • What can I do if my symptoms come back after treatment?

Don't hesitate to ask questions during your appointment if you don't understand something.

Questions your doctor may ask

Be prepared to answer questions your doctor may have, such as:

  • What symptoms are you experiencing?
  • How long have you had your symptoms?
  • Do you notice a strong vaginal odor?
  • Have you ever been treated for a vaginal infection?
  • Have you tried any products you can buy without a prescription to treat your condition?
  • Have you recently taken antibiotics for any reason?
  • Are you sexually active?
  • Are you pregnant?
  • Do you use scented soap or bubble bath?
  • Do you douche or use feminine hygiene spray?

Content From Mayo Clinic Updated: 06/09/2023
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