What are Probiotics Used For?

Discover 6 uses of probiotics to keep you feeling healthy.

Probiotics, micro-organisms made up mostly of bacteria, are used to help with a variety of health conditions. The most studied probiotics are the bacterial species of Lactibacillus, and Bifidobacterium as well as the yeast species of Saccharomyces. These are micro-organisms that are commonly found in our gut. 

When using probiotics it is important to know the species, dose, frequency and duration for an effective treatment. 

So, what are probiotics used for?

1. Prevent or treat diarrhea caused by antibiotics

Lady with abdominal pain

One of the most common ways that probiotics are used is to prevent or treat diarrhea caused by antibiotics.

When you take antibiotics they kill both good and bad bacteria in your body. When the good bacteria in your colon are destroyed then the bad bacteria can grow causing diarrhea.

Taking probiotics when starting an antibiotic can reduce your chances of getting diarrhea.

In general, taking a probiotic daily while on the antibiotic and for 2 weeks afterward is a good start to keep you healthy. I am frequently asked...

"Do I have to take the antibiotic and probiotic at different times?"

No, you can take them at the same time

You do need to take a probiotic that has a minimum of 10 billion Colony-Forming Units (CFUs) daily and that has multiple strains of bacteria. This can be used preventatively or after diarrhea has already started.

Mini Med School

Colony-Forming Units or (CFUs) are how many bacteria will grow in a lab test and is used as a marker for the dose of probiotics.  A good probiotic should list how many CFUs there are in a dose. 

References (1) 

2. Infectious Diarrhea

Research shows the benefits of probiotics for diarrhea. Taking a probiotic at the beginning of having diarrhea can shorten how long you are sick by about 1 day (16-26 hours). The most commonly studied form of probiotics were the Lactobacillus species.
Keep reading to learn how to get rid of a stomach bug for good with probiotics. 

References (1)

3. Traveler's diarrhea

Photo of items you need to travel

When traveling outside of the US you could get traveler's diarrhea. This is most commonly caused by exposure to bacteria in water or improperly prepared foods. 

Probiotics can be taken preventatively to avoid getting diarrhea on your trip. (No one wants to spend their vacation to Mexico in the bathroom instead of soaking up rays on the beach). 

Start taking the probiotic 2 days prior your trip for best results. 

Studied probiotics were Saccharomyces boulardii, and a mixture of lactobacillus acidophilus and Bifidobacterium bifidum

References (2)

4. Irritable Bowel Syndrome (IBS)

Another use of probiotics is for IBS. 

An excellent study was published in July 2020 showing benefits of probiotics for IBS. It was a double-blind randomized controlled trial specifically studying a species of bacteria, Bifidobacterium bifidum.

Mini Med School

Randomized controlled trials (RCTs) are the most respected form of clinical studies. To avoid bias in the study the participants are randomly assigned to a treatment group or a control group. The best studies are blinded so the patient and ideally the researcher/doctor don't know if the patient is getting the treatment or control. The only type of study that is better than this is a meta-analysis of multiple RCTs -- multiple RCTs are reviewed and the data is compiled to verify that the same results are obtained in more that 1 study. 

This study shows significant improvement in IBS sufferers who took 1 billion units of non-viable B bifidum HI-MIMBb75 cells for 8 weeks. 

References (3)

4. Group B Strep (GBS)

Group B strep is a bacteria that is commonly found in the birth canal (15-40% of pregnant women). It doesn't cause any problems for the mother and is not a considered a sexually transmitted infection. 

It is a concern for being a major cause of infections in newborn babies. It could cause an infection in the brain / brain lining (meningitis), lungs (pneumonia), and blood stream (sepsis). 

Currently, the treatment plan is for pregnant mothers to get 4 hours of IV antibiotics while in labor to kill off the GBS prior to the newborn passing through the birth canal. 

Although more research needs to be done, taking probiotics can reduce the chances of being colonized with GBS and thus avoid transfer to the baby and the need for antibiotics. 

References (4,5)

5. Bacterial Vaginosis (BV)

Many studies have been conducted to test the benefit of probiotics for the treatment of bacterial vaginosis. 

The best results are using 2 specific strains of Lactobacillus taken orally in conjunction with the typical treatment of metronidazole 500 mg twice a day for 7 days.

The treatment regimen for the probiotics is:
Lactobacillus rhamnosus GR-1 1 billion CFUs and Lactobacillus reuteri RC-14 1 billion CFUs taken 1 capsule twice a day for 30 days starting on the first day of treatment with metronidazole.

References (6) 

6. Mastitis

Mother holding an infant

Mastitis can be a very painful experience for a breastfeeding mother. Research studies show that the use of probiotics taken in late pregnancy (30 weeks until delivery), can lower the risk of developing mastitis when starting to breast feed. 

Taking Lactobacillus salivarius PS2 at a dose of 1 billion CFUs per capsule daily during late pregnancy, can lower the chances of getting mastitis. 

Probiotics can also be used to treat mastitis. A study of 352 women with mastitis showed that either the probiotic of:

  • Lactobacillus salivarius CECT5713 at a dose of 1 billion CFUs


  • Lactobacillus fermentum CECT5716 at a dose of 1 billion CFUs

When taken daily for 3 weeks had better improvement in pain and lower recurrence than ladies who took antibiotics.

References (7, 8)

So... what are probiotics used for?

As you can see, probiotics can be used for so many things. The next time you are sick and thinking of taking an antibiotic ask, "Will a probiotic work instead?" and if you are starting and antibiotic consider taking a probiotic with it. 

References for "What are probiotics used for?"

1.  Wilkins T, Sequoia J. Probiotics for gastrointestinal conditions: a summary of the evidence. Am Fam Physician. 2017 Aug 1;96(3):170-178. 
2. Bae JM. Prophylactic efficacy of probiotics on travelers' diarrhea: an adaptive meta-analysis of randomized controlled trials. Epidemiol Health. 2018;40:e2018043. 
3. Andresen V, Gschossmann J, Layer P. Heat-inactivated Bifidobacterium bifidum MIMBb75 (SYN-HI-001) in the treatment of irritable bowel syndrome: a multicentre, randomised, double-blind, placebo-controlled clinical trial. Lancet Gastroenterol Hepatol. 2020;5(7):658-666.
4. Martín V, Cárdenas N, Ocaña S, et al. Rectal and Vaginal Eradication of Streptococcus agalactiae (GBS) in Pregnant Women by Using Lactobacillus salivarius CECT 9145, A Target-specific Probiotic Strain. Nutrients. 2019;11(4):810. Published 2019 Apr 10. doi:10.3390/nu11040810
5. Ho M, Chang YY, Chang WC, et al. Oral Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 to reduce Group B Streptococcus colonization in pregnant women: A randomized controlled trial. Taiwan J Obstet Gynecol. 2016;55(4):515-518. 

6Anukam K, Osazuwa E, Ahonkhai I, et al. Augmentation of antimicrobial metronidazole therapy of bacterial vaginosis with oral probiotic Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14: randomized, double-blind, placebo controlled trial. Microbes Infect. 2006;8(6):1450-1454. 
7. Fernández L, Cárdenas N, Arroyo R, et al. Prevention of Infectious Mastitis by Oral Administration of Lactobacillus salivarius PS2 During Late PregnancyClin Infect Dis. 2016;62(5):568-573.
8. Arroyo R, Martín V, Maldonado A, Jiménez E, Fernández L, Rodríguez JM. Treatment of infectious mastitis during lactation: antibiotics versus oral administration of Lactobacilli isolated from breast milk. Clin Infect Dis. 2010;50(12):1551-1558.