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Home > Be Healthy > Health Library > Bacterial Vaginosis
Bacterial vaginosis is a mild infection of the vagina caused by bacteria. Normally, there are a lot of "good" bacteria and some "bad" bacteria in the vagina. The good types help control the growth of the bad types. In women with bacterial vaginosis, the balance is upset. There are not enough good bacteria and too many bad bacteria.
Bacterial vaginosis is usually a mild problem that may go away on its own in a few days. But it can lead to more serious problems. So it's a good idea to see your doctor and get treatment.
Experts are not sure what causes the bacteria in the vagina to get out of balance. But certain things make it more likely to happen. Your risk of getting bacterial vaginosis is higher if you:
You may be able to avoid bacterial vaginosis if you limit your number of sex partners and don't douche or smoke.
Bacterial vaginosis is more common in women who are sexually active. But it can occur if you are not sexually active as well.
The most common symptom is a smelly vaginal discharge. It may look grayish white or yellow. A sign of bacterial vaginosis can be a "fishy" smell, which may be worse after sex. About half of women who have bacterial vaginosis do not notice any symptoms.
Many things can cause abnormal vaginal discharge, including some sexually transmitted infections (STIs). See your doctor so you can be tested and get the right treatment.
Doctors diagnose bacterial vaginosis by asking about the symptoms, doing a pelvic exam, and taking a sample of the vaginal discharge. The sample can be tested to find out if you have bacterial vaginosis.
Bacterial vaginosis usually does not cause other health problems. But in some cases it can lead to serious problems.
Doctors usually prescribe an antibiotic to treat bacterial vaginosis. They come as pills you swallow or as a cream or capsules (called ovules) that you put in your vagina. If you are pregnant, you will need to take pills.
Bacterial vaginosis usually clears up in 2 or 3 days with antibiotics, but treatment goes on for 7 days. Do not stop using your medicine just because your symptoms are better. Be sure to take the full course of antibiotics.
Antibiotics usually work well and have few side effects. But taking them can lead to a vaginal yeast infection. A yeast infection can cause itching, redness, and a lumpy, white discharge. If you have these symptoms, talk to your doctor about what to do.
Bacterial vaginosis is caused by an imbalance of the organisms (flora) that naturally exist in the vagina. Normally, about 95% of vaginal flora are lactobacillus bacteria. (These types are unique to humans, different from the lactobacillus in yogurt.) These lactobacilli help keep the vaginal pH level low and prevent overgrowth of other types of organisms. Women with bacterial vaginosis have fewer lactobacillus organisms than normal and more of other types of bacteria. Experts do not yet understand what causes this imbalance.
Although the specific cause isn't known, a number of health and lifestyle factors have been linked to bacterial vaginosis. For more information, see What Increases Your Risk.
Many women with bacterial vaginosis do not have any symptoms. Bacterial vaginosis does not typically cause itching. But it does cause:
Other conditions with similar symptoms include some sexually transmitted infections (especially trichomoniasis, chlamydia, and gonorrhea) and vaginal yeast infection.
Bacterial vaginosis often clears up on its own. But in some women it doesn't go away on its own. And for many women it comes back after it has cleared up. Antibiotic treatment works for some women but not others.
Your risk of complications from bacterial vaginosis is higher:
Things that increase your risk of getting bacterial vaginosis include:
Although bacterial vaginosis can be triggered by or get worse from sexual activity, it does not appear to be an infection that is passed from man to woman. So experts do not consider bacterial vaginosis to be a male-female sexually transmitted infection. Bacterial vaginosis may be passed from woman to woman during sexual contact.
Bacterial vaginosis can be hard to distinguish from other types of vaginal infection. Consider the following if you have any signs of vaginal infection.
Call your doctor immediately if you:
Call your doctor for an appointment within 1 week if you:
If you have not been diagnosed with bacterial vaginosis but you have symptoms that concern you, see:
It's generally recommended that you contact or see your doctor about unusual vaginal symptoms.
If your symptoms are due to a sexually transmitted infection (STI) and not bacterial vaginosis, you may infect a sex partner if you delay treatment. You may also develop more serious complications of STIs such as pelvic inflammatory disease (PID).
Doctors who can diagnose and treat bacterial vaginosis include:
Your doctor may test you for bacterial vaginosis if you:
Your doctor can diagnose bacterial vaginosis based on your history of symptoms, a vaginal exam, and a sample of the vaginal discharge. Laboratory tests to detect signs of bacterial vaginosis may include:
The presence of clue cells, an increased vaginal pH, and a positive whiff test are enough evidence to treat for bacterial vaginosis.
Bacterial vaginosis may be found during a pelvic exam.
Treatment for bacterial vaginosis includes antibiotic medicine (oral or vaginal). Antibiotics kill the problem bacteria causing bacterial vaginosis symptoms. But symptoms often come back after antibiotic treatment.
For some women, bacterial vaginosis goes away without treatment. But when it does not go away even with treatment, bacterial vaginosis is frustrating and troublesome. Bacterial vaginosis makes the reproductive tract vulnerable to infection or inflammation. So your doctor will test and treat you with antibiotics for bacterial vaginosis if you are:
Talk to your doctor about whether testing is right for you.
If your doctor finds other problems during the exam, such as a possible sexually transmitted infection (STI), appropriate treatment will be recommended.
To help prevent bacterial vaginosis:
Bacterial vaginosis may be passed between women during sexual contact. If you have a female sex partner, you may benefit from using protection and carefully washing shared sex toys.
Bacterial vaginosis is generally not considered a sexually transmitted infection (STI). But if you are exposed to an STI while you have bacterial vaginosis, you are more likely to get that infection.
It is always important to practice safer sex to prevent sexually transmitted infections, whether or not you have bacterial vaginosis. Preventing an STI is easier than treating an infection after it occurs.
Some women have tried treating bacterial vaginosis with the probiotic Lactobacillus. This is found in foods like yogurt and in dietary supplements. But more research is needed to find out if Lactobacillus works to treat or prevent bacterial vaginosis.
There are also different types of Lactobacillus, and researchers don't yet know which type would be most effective.
The antibiotics metronidazole (such as Flagyl and MetroGel), clindamycin (such as Cleocin and Clindesse), and tinidazole (such as Tindamax) are used to treat bacterial vaginosis. Depending on the antibiotic you are prescribed, you may take it by mouth or use it vaginally.
During pregnancy, women are usually prescribed oral medicine.
When considering treatment for bacterial vaginosis, ask your doctor whether you should:
The oil in clindamycin cream and ovules can weaken latex. This means condoms and diaphragms may break, and you may not be protected from STIs or pregnancy.
Other Works Consulted
Abramowicz M (2010). Drugs for sexually transmitted infections. Treatment Guidelines From The Medical Letter, 8(95): 53–60.
American College of Obstetricians and Gynecologists (2006, reaffirmed 2011). Vaginitis. ACOG Practice Bulletin No. 72. Obstetrics and Gynecology, 107(5): 1195–1206.
Bornstein J (2013). Benign disorders of the vulva and vagina. In AH DeCherney et al., eds., Current Diagnosis and Treatment Obstetrics and Gynecology, 11th ed., pp. 620–645. New York: McGraw-Hill.
Eckert LO, Lentz GM (2012). Infections of the lower and upper genital tracts: Vulva, vagina, cervix, toxic shock syndromes, endometriosis, and salpingitis. In GM Lentz et al., eds., Comprehensive Gynecology, 6th ed., pp. 519–559. Philadelphia: Mosby.
Mackay G (2013). Sexually transmitted diseases and pelvic infections. In AH DeCherney et al., eds., Current Diagnosis and Treatment Obstetrics and Gynecology, 11th ed., pp. 701–731. New York: McGraw-Hill.
Marrazzo J, Sobel J (2010). Vaginal infections. In SA Morse et al., eds., Atlas of Sexually Transmitted Diseases and AIDS, 4th ed., pp. 76–85. Philadelphia: Saunders.
Soper DE (2012). Genitourinary infections and sexually transmitted diseases. In JS Berek, ed., Berek and Novak's Gynecology, 15th ed., pp. 557–573. Philadelphia: Lippincott Williams and Wilkins.
Current as of:
February 19, 2019
Author: Healthwise StaffMedical Review: Sarah Marshall MD - Family MedicineKathleen Romito MD - Family MedicineMartin J. Gabica MD - Family MedicineDevika Singh MD, MPH - Infectious Disease
Current as of:
February 19, 2019
Medical Review:Sarah Marshall MD - Family Medicine & Kathleen Romito MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Devika Singh MD, MPH - Infectious Disease
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