Probiotics

Also known as probiotic, lactobacillus, bifidobacterium, probiotics blend, probiotic.

Last reviewed October 9, 2026 · Jump to references

What is Probiotics?

In plain words

Probiotics are live bacteria or yeasts that can benefit health. Some survive digestion and interact with the gut and its resident microbes, usually without becoming permanent residents. Researchers study specific types for digestive health, including some forms of diarrhea. Benefits depend on the exact type, and serious infections can occur rarely, especially in people with weakened immune systems.

Technical definition

Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host; they include specific strains of bacteria such as Lactobacillus and Bifidobacterium, as well as certain yeasts. Rather than acting through a single molecular target, they can interact with intestinal microbes, epithelial barriers, and immune signaling through strain-specific mechanisms, including metabolite production and competition with pathogens. Regulatory classification varies by country and product; in the United States, many are marketed as foods or dietary supplements rather than approved drugs.

Educational information only. This page does not provide medical advice or determine whether a supplement is appropriate for you. Review supplements with a qualified healthcare professional, especially if you take medication, are pregnant, have surgery scheduled, or have a chronic medical condition.

Evidence by use

Each use is rated on its own. There is no single overall effectiveness score.