Probiotics 101: What They Are and When to Use

Probiotics are live bacteria and yeasts similar to the microorganisms that naturally live in your gut. They help promote a healthy bacteria balance in the gut by counteracting unhealthy gut bacteria from a poor diet, inflammation, antibiotics, and illnesses. Probiotics help restore the natural balance of gut bacteria.

When it comes to probiotics, scientists have discovered there’s a wide variety of different types and therefore, probiotics are differentiated by the strain of bacteria. If you’ve ever looked for a probiotic, you’ve probably been a little overwhelmed and confused with the long and complicated names. There is a good chance you’ve said something like, “I was told to take a probiotic, but what does Lactobacillus acidophilus or Bifidobacteria longum even mean?”

In an effort to help simplify things, I’m sharing a few common strains of probiotics, what ailments they treat, and where to find them.

Lactobacillus acidophilus (L. acidophilus)

Primary Purpose:

  • Digestion and overall general health. L. acidophilus helps break down sugars such as lactose, into lactic acid. It is also known for protecting against harmful germs.


May also help:

  • Reduce cholesterol

  • Improve symptoms associated with chronic fatigue syndrome

  • Prevent or reduce diarrhea

  • Improve symptoms of IBS

  • Treat and prevent vaginal yeast infections

  • Boost immune system


Found in: Naturally found in fermented foods such as sauerkraut, miso, and tempeh. Commonly added to foods such as cheese and yogurt. Can also be found in a supplement.

Lactobacillus rhamnosus (L. rhamnosus)

Primary purpose:

  • Prevent and treat a variety of types of diarrhea, specifically antibiotic-related diarrhea.


May also help:

  • Relieve symptoms of irritable bowel syndrome (IBS)

  • Improve overall gut health

  • Protect against cavities due to the antimicrobial properties.


Found in: Supplements and often added to dairy products such as yogurt, cheese, and milk.

Lactobacillus casei (L. casei)

Primary Purpose:

  • Prevent and treat diarrhea, including infectious diarrhea, traveler’s diarrhea and diarrhea associated with taking antibiotics.


May also help:

  • Reduce symptoms of other digestive issues such as constipation, Crohn's disease, IBD (inflammatory bowel disease), IBS (irritable bowel syndrome) and ulcerative colitis.


Found in: Fermented foods such as yogurt, milk, and cheese. Also found in supplements.

Bifidobacteria longum (B. longum)

Primary Purpose:

  • Boost immune system


May also help:

  • Decrease inflammation

  • Decrease cholesterol

  • Improve gut health

  • Boost brain function

  • Improves mood


Found in: Naturally found in fermented foods such as sauerkraut, yogurt, kefir, kombucha, tempeh, and miso.

Saccharomyces boulardii (S. boulardii)

Primary Purpose:

  • Treating rotaviral diarrhea in children and diarrhea caused by antibiotics.


May also help:

  • Acne

  • Diarrhea caused by “bad” bacteria overgrowth in adult

  • Traveler’s diarrhea

  • Diarrhea associated with tube feeding


Found in: S. Boulardii is actually yeast and easiest to take in the over-the-counter supplement form. Can also be found in African fermented foods such as kenkey, ogi, and amasi.