Skip to Content
Home > Health Information > Health Library > 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
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.
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
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
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.
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.
Learning about bacterial vaginosis:
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.
specific cause isn't known, a number of health and lifestyle factors have been
linked to bacterial vaginosis. For more information, see What Increases
Many women with bacterial vaginosis do not have any symptoms. Bacterial vaginosis does not typically cause itching. But it
Other conditions with similar symptoms include some
sexually transmitted infections (especially
trichomoniasis, chlamydia, and gonorrhea)
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
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
Call your doctor immediately if
Call your doctor for an appointment within 1 week if
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.
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
To prepare for your appointment, see the topic Making the Most of Your Appointment.
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
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.
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
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 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
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 used
Lactobacillus acidophilus in yogurt or supplements to
bacterial vaginosis. But dairy lactobacillus does not
work for bacterial vaginosis. This is because dairy lactobacillus is not the
kind of bacteria that normally live in the vagina.
More research is needed to find out if the types of lactobacillus normally found in a healthy vagina may work to treat bacterial vaginosis.
antibiotics metronidazole (such as Flagyl and MetroGel),
clindamycin (such as Cleocin and Clindesse), and tinidazole (such as Tindamax) are used to
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.
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.
ByHealthwise StaffPrimary Medical ReviewerSarah Marshall, MD - Family MedicineKathleen Romito, MD - Family MedicineSpecialist Medical ReviewerDevika Singh, MD, MPH - Infectious Disease
Current as ofOctober 6, 2017
Current as of:
October 6, 2017
Sarah Marshall, MD - Family Medicine & Kathleen Romito, MD - Family Medicine & Devika Singh, MD, MPH - Infectious Disease
To learn more about Healthwise, visit Healthwise.org.
© 1995-2018 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Our interactive Decision Points guide you through making key health decisions by combining medical information with your personal information.
You'll find Decision Points to help you answer questions about:
Get started learning more about your health!
Our Interactive Tools can help you make smart decisions for a healthier life. You'll find personal calculators and tools for health and fitness, lifestyle checkups, and pregnancy.
Feeling under the weather?
Use our interactive symptom checker to evaluate your symptoms and determine appropriate action or treatment.
See important information from Billings Clinic on Non-discrimination and Interpreter Services.
Billings Clinic is proud to be an equal opportunity/affirmative action (EOE/AA) e-verify employer.