Probiotics are living good bacteria’s that provide health benefits to the human body when ingested in adequate amounts. probiotics include lactic acid bacteria and bifidobacteria most frequently. Probiotics shows the antagonistic effects on various microorganisms include the following: modification of the gut microbiota, competitive adherence to the mucosa and epithelium, strengthening of the gut epithelial barrier and modulation of the immune system to convey an advantage to the host. Probiotics shows beneficial action or interact with the body by pattern recognition receptors, such as toll-like receptors and nucleotide-binding oligomerization domain-containing protein-like receptors, which regulates important signaling pathways, such as nuclear factor-ĸB and protein kinase, to enhance or suppress activation and influence downstream pathways. The mentioned pathways or receptors are important for eliciting measured antimicrobial responses with minimal inflammatory tissue damage. probiotic strain selection for specific applications can be decided after a clear understanding of these mechanisms and may also uncover novel probiotic functions.