Consuming probiotics has become a popular way to improve digestive health. Probiotics are healthy bacteria strains found naturally in some foods and in nutritional supplements.

More recently, health experts have begun to consider the potential benefits of probiotics on vaginal health. The scientific evidence is not conclusive. However, it appears that at least one strain of probiotic, L. acidophilus, could help prevent and treat vaginal imbalance issues like bacterial vaginosis (BV).

Experts say more research is needed.

“There has been promising research in the past few years indicating that probiotics may be effective in treating some conditions precipitated by changes in vaginal pH balance,” says Mindy Haar, PhD, RDN, CSN, of the New York Institute of Technology’s Department of Interdisciplinary Health Sciences.

More than 50 different species of tiny organisms (called microbes) live inside your vagina. Many of these microbes are a type of bacteria called lactobacilli. These bacteria help keep the vagina healthy and free of infection.

A lack of lactobacilli and an overgrowth of some other microbe can cause an imbalance in the vagina. This imbalance can occur for a number of reasons, including when a woman:

  • has unprotected sex with a male partner
  • experiences changes in hormones
  • is having her period
  • does not maintain good hygiene habits

A vaginal imbalance can result in a:

  • fishy odor
  • discharge
  • discomfort
  • itching

Vaginal imbalances can result in:

Having a vaginal imbalance may also increase your chances of a urinary tract infection (UTI). However, it’s important to note that UTIs are not always caused by the same pathogens that cause vaginal infections.

Read on to learn more about these issues:

Bacterial vaginosis (BV)

The most common vaginal imbalance issue is bacterial vaginosis (BV). Women with BV have high numbers of many different species of bacteria in their vaginas. Healthy women have lower numbers of fewer species of bacteria in their vaginas.

These additional bacteria cause the pH of the vaginal to elevate above 4.5. This reduces the number of lactobacilli present in the vagina. Besides an elevated vaginal pH, women with BV often experience:

  • a fishy odor
  • burning during urination
  • a milky or gray vaginal discharge
  • itching

Doctors say they aren’t completely certain what causes BV, but some factors appear to put some women at a higher risk. These include:

  • having more than one sexual partner or a new sexual partner
  • douching, or rinsing your vagina with soap and water (the vagina cleanses itself and douching can disrupt its natural balance)
  • a natural lack of lactobacilli bacteria (some women don’t have high levels of good bacteria present in their vaginas, which can lead to BV)

Treatment of BV most often includes use of antibiotic medication. These are given orally or as a gel that’s inserted into the vagina. Some doctors may also recommend a probiotic in addition to — but not in lieu of — antibiotics.

Yeast infection

Yeast infection is another type of vaginal imbalance issue. Most cases of yeast vaginitis are caused by a fungus called candida albicans. Other types of fungus may also cause this condition.

Usually, growth of fungus is kept in check by good bacteria. But an imbalance of vaginal bacteria, especially having too little lactobacillus, can cause fungus to grow out of control inside the vagina.

A yeast infection can range from mild to moderate. Symptoms include:

  • irritation
  • a thick white or watery discharge
  • intense itching in the vagina and vulva
  • a burning sensation during sex or urination
  • pain and soreness
  • vaginal rash

The overgrowth of yeast that results in a yeast infection may be caused by:

  • antibiotics, which can cause kill off the good bacteria in your vagina
  • pregnancy
  • uncontrolled diabetes
  • an impaired immune system
  • taking oral contraceptives or other type of hormone therapy that increases estrogen levels

Most yeast infections can be treated with a short course of antifungal medication. These are available as:

  • topical creams
  • topical ointments
  • oral tablets
  • vaginal suppositories

In other cases, your doctor may recommend a single dose of oral antifungal medication, or a combination of medications.


Trichomoniasis is a very common sexually transmitted infection (STI). According to the Centers for Disease Control and Prevention (CDC), 3.7 million Americans are infected with trichomoniasis at any given time.

Symptoms of trichomoniasis include:

  • itching, burning, redness or soreness
  • discomfort when urinating
  • change in vaginal discharge: either a thin amount or noticeably more; it may be clear, white, yellow, or greenish with an unusual fishy smell.

Antibiotics (metronidazole (Flagyl) or tinidazole (Tindamax) are the recommended treatment for trichomoniasis. Probiotics would not be used as a treatment or even a preventative method. However, it’s worth noting that having vaginal imbalance such as BV can increase your chances of getting an STI like trichomoniasis.

Urinary tract infection (UTI)

Although your urethra is close to your vagina, urinary tract infections (UTIs) are not always caused by the same pathogens that cause vaginal infections. That said, having healthy vagina flora may help prevent harmful bacterial from entering your urinary tract.

UTIs occur when bacteria enter the urinary tract through the urethra and begin to multiply in the bladder. While the urinary system is designed to keep foreign bacteria out, they sometimes enter and cause an infection.

Most UTIs affect only the bladder and urethra. A UTI becomes more serious when it spreads to your kidneys, where it can cause a life-threatening infection.

A UTI does not always cause symptoms that are easy to recognize. Some more common symptoms include:

  • the need to urinate more frequently
  • a burning sensation during urination
  • passing small amounts of urine
  • passing urine that appears cloudy, bright red, pink, or cola colored
  • passing strong-smelling urine
  • pelvic pain, especially around the center of the pelvis and the area of the pubic bone

UTIs are more common in women. This is because women have shorter urethras than men, making it easier for bacteria to enter. Other risk factors for developing a UTI include:

  • sexual activity
  • having a new sexual partner
  • certain types of birth control, such as diaphragms and spermicides
  • menopause
  • physical issues within the urinary system
  • blockages in the urinary system
  • a suppressed immune system
  • use of a catheter
  • a recent urinary exam or surgery

With most UTIs, doctors will recommend use of antibiotics.

The type of antibiotic your doctor prescribes depends upon several factors, including:

  • the type of bacteria found in your urine
  • your health status
  • how long you’ve been dealing with your infection

For severe UTIs, you may need treatment with intravenous antibiotics in a hospital setting.

Experts say no conclusive evidence shows that probiotics are effective at preventing and treating BV or other conditions related to vaginal imbalance. Currently, antibiotics remain the recommended treatment for these conditions.

“As it’s important to get a proper diagnosis and treat underlying causes, the recommendation to take a probiotic in supplement form should be made by the healthcare provider only after a complete assessment and proper diagnosis of the condition is made,” says Haar.

The evidence

Some scientific evidence suggests probiotics in yogurt, capsules, and vaginal suppositories may help prevent and treat imbalance in the vagina.

In a small 1996 study, doctors found that women who ate probiotic yogurt containing lactobacillus acidophilus had a larger amount of lactobacillus bacteria in their vaginas than those who did not. The women who ate this probiotic yogurt were also less likely to experience BV than the women who did not. These results suggest the probiotic had some kind of protective effect against vaginal imbalance.

Similarly, other small studies suggest that taking a daily probiotic capsule can be effective in preventing and treating vaginal imbalance.

In one study, half the members of a small group of women with BV were given antibiotics for 7 days, while the other half were given antibiotics with a probiotic or placebo for 30 days. The cure rate at 30 days was close to 90 percent in the antibiotic-plus-probiotic group, in contrast to 40 percent in the antibiotic-plus-placebo group.

In another small study of 42 healthy women, taking just a probiotic alone was enough to cure BV and maintain healthy levels of bacteria in the vagina. It’s worth noting that asymptomatic BV may respond differently than BV with notable vaginal symptoms and high levels of bacteria present.

Other studies have investigated the effects of using a vaginal probiotic suppository to treat BV. In one small study, researchers found that 57 percent of the women who used a lactobacillus vaginal suppository were able to cure their BV and also maintain a healthy balance of vaginal bacteria following treatment. However, the effects were not maintained in very many of the subjects. Only three of the women (11 percent) who received the lactobacillus suppository were free of BV after their subsequent menstruation.

While the results of these studies are encouraging, most studies looking at the effects of probiotics on vaginal balance are small and limited in scope. More research is needed to definitively determine whether or not probiotics are an appropriate treatment for vaginal imbalance issues.

Lactobacillus acidophilus is the most-researched strain of probiotic when it comes to establishing and maintaining a healthy vaginal balance. Two other important strains include lactobacillus rhamnosus and lactobacillus reuteri.

Experts believe these strains help maintain vaginal balance by sticking to vaginal surfaces and making it more challenging for harmful bacteria to grow. Lactobacillus may also adhere directly to harmful bacteria, killing them and preventing them from spreading.

When it comes to probiotics, most experts recommend consuming whole food rather than supplements. “Getting these helpful micro-organisms from the diet rather than supplement products brings no risk and that’s why I recommend focusing on diet rather than pills. Yogurt that contains live cultures is the best source of lactobacilli.”

Haar also adds that reducing your sugar intake may also be a good way to reduce growth of harmful bacteria in the vagina. She recommends a diet rich in probiotics, as well as lots of fresh fruits, vegetables, and whole grains. These foods are considered “prebiotics,” which help promote growth of healthy probiotic bacteria in the body.

Dive Deeper: A Dietitian’s List of Best Probiotics for Women

Usually, conditions caused by vaginal imbalance are mild to moderate, and don’t cause severe health problems. However, BV and yeast infections can cause serious discomfort if left untreated. And you should always seek quick treatment for a UTI to avoid possible complications.

If you’ve recently had sex and notice itching, burning or other unusual symptoms in your vaginal area, you should also talk with your doctor. You could have a sexually transmitted infection, such as trichomoniasis.

Schedule an appointment with your doctor if you suspect you have BV, a yeast infection, or a UTI. Seek immediate medical treatment if you have:

  • pain on your sides or lower back
  • a high temperature
  • shivers
  • feel ill
  • diarrhea

These are signs of a kidney infection, which can be serious when left untreated.

More research is needed to determine whether or not probiotics are a reliable way to prevent and treat vaginal imbalance and the conditions it can cause. However, some research suggests using probiotics may be useful in treating and establishing a healthy vaginal balance. Taking a probiotic is a possibly beneficial behavior, with no known risks for healthy women.