Probiotics vs Prebiotics: What's the Difference?

By the TopTierFind Editorial Team · Facts checked 2026-10-16

Probiotics are live microorganisms, and prebiotics are compounds the body does not fully digest, many of them types of fiber, that feed beneficial gut bacteria. University of Rochester Medicine says most people can support gut health through a balanced diet rather than supplements. If you are considering a probiotic supplement, the National Center for Complementary and Integrative Health (NIH) says to consult your health care provider first.

Probiotics vs prebiotics at a glance

	Probiotics	Prebiotics
What they are	Live beneficial microorganisms	Non-living, fiber-like compounds
Main role	Add beneficial bacteria and help maintain balance	Nourish good gut bacteria
Common sources	Fermented foods and some supplements	Fiber-rich plant foods

The comparison above follows the table on the University of Rochester Medicine page.

What are probiotics?

The NIH’s NCCIH describes probiotics as live microorganisms that are intended to have health benefits when consumed or applied to the body. Cleveland Clinic describes them as live bacteria and yeasts that have beneficial effects on your body. It says two main genera of friendly bacteria in human intestines are Lactobacillus and Bifidobacterium.

University of Rochester Medicine says probiotics help keep the gut microbiome balanced. The microbiome is the community of trillions of bacteria in your digestive tract.

What are prebiotics?

Cleveland Clinic says prebiotics are a type of carbohydrate our bodies are unable to digest, and that they feed the good bacteria in your gut. Its analogy is that probiotics are the seeds you plant in your garden (your gut microbiota) and prebiotics are the fertilizer that helps them grow.

Do you need them?

Cleveland Clinic says that in a healthy state you will not need pre- or probiotics if you already have a good balance of friendly bacteria. It quotes dietitian Gail Cresci saying people don’t eat the 25 to 35 grams of fiber the gut bacteria need. It also says a chronic disease can leave too few friendly bacteria in the gut.

University of Rochester Medicine says most people can support gut health through a balanced diet rather than supplements.

Food sources

These lists come from University of Rochester Medicine.

Probiotic foods

• Yogurt, kefir, miso, kimchi, sauerkraut and tempeh.
• Cleveland Clinic also lists kombucha (a fermented tea) among fermented foods, and notes that yogurt may contain added Lactobacillus and Bifidobacterium strains.

Prebiotic foods

• Slightly under-ripe bananas, onions, garlic, apples, tomatoes and oats.

What about prebiotic sodas?

University of Rochester Medicine says whole-food fiber sources are generally a better choice than prebiotic sodas. It makes these points:

• Prebiotic sodas typically contain added fiber such as inulin, a fiber found naturally in many plants, which supports regularity.
• Too much inulin, especially from artificial sources, can cause gas, cramping or bloating. Carbonation can cause similar symptoms.
• They usually contain under 5 grams of added sugar per can, much less than traditional soda.
• If your diet is low in fiber, adding these drinks may trigger GI symptoms.
• Whole foods provide vitamins and minerals and tend to be more filling.

Checklist: supporting your gut

University of Rochester Medicine’s gut health checklist includes:

• Eat a variety of fruits and vegetables.
• Choose whole grains and fiber-rich foods.
• Include fermented foods when appropriate.
• Stay hydrated.
• Exercise regularly.
• Talk with a healthcare professional before starting supplements.

When to talk to a doctor or dietitian

University of Rochester Medicine says people with inflammatory bowel conditions (such as IBS or Crohn’s disease), food intolerances, or other gastrointestinal conditions may benefit from individualized care, and should consult their healthcare provider and a registered dietitian.

It also says clinicians may recommend probiotics after one or more courses of antibiotics, after a gastrointestinal illness, or whenever the gut microbiome has been significantly altered, and that this should be guided by a healthcare provider.

The NCCIH adds that:

• If you’re considering a probiotic dietary supplement, consult your health care provider first.
• The risk of harmful effects from probiotics is greater in people with severe illnesses or compromised immune systems.
• Severe or fatal infections have been reported in premature infants who were given probiotics.
• Don’t use probiotics as a reason to postpone seeing your health care provider about any health problem.

Cleveland Clinic likewise says people with a chronic disease or weakened immune system should consult a doctor before changing their probiotic intake. For sudden or severe symptoms, contact your doctor or local emergency services (911 in the US).

The short version

• Probiotics are live microorganisms. Prebiotics are non-living, fiber-like compounds that feed gut bacteria.
• Both are available from everyday foods, and most people can support gut health through a balanced diet.
• Prebiotic sodas are not a better choice than whole foods, and too much inulin can cause gas, cramping or bloating.
• Ask a healthcare provider before starting supplements, especially if you have a digestive condition or a weakened immune system.

This guide is general information based on the sources below. It is not medical advice.

Keep reading

• How to Check If a Supplement Is Legit in Your Country (US, UK, Canada, Australia, NZ)
• How to Spot a Supplement Scam: Fake Reviews and “Doctor-Approved” Claims
• How to Cancel a Supplement Free Trial and Get a Refund
• All guides: Weight Loss and Gut Health: Every Guide in One Place

Not sure what fits you? Take the 1-minute gut health quiz →

Sources

• Prebiotics vs. Probiotics: What’s the Difference and Do You Need Both? (University of Rochester Medicine)
• Prebiotics vs. Probiotics: What’s the Difference? (Cleveland Clinic)
• Probiotics: Usefulness and Safety (NIH, NCCIH)