Prebiotics and probiotics are increasingly used in poultry production to enhance health and reduce the risk of enteric diseases. The intestinal microbiota, epithelium, and immune system work together to resist pathogens. Mechanisms of resistance include competition for colonization sites, nutrient competition, production of toxic compounds, and immune stimulation. Lactic acid bacteria (lactobacilli and bifidobacteria) are believed to improve health through these mechanisms. Research shows that probiotics and prebiotics can increase resistance to disease by modulating the intestinal microbiota and immune system. Prebiotics are non-digestible food ingredients that selectively stimulate the growth of beneficial bacteria, while probiotics are live microorganisms that beneficially affect the host. Synbiotics combine prebiotics and probiotics for enhanced effects. Probiotics and prebiotics have been used for centuries, either as natural components of food or as fermented foods. Interest in their use in poultry has grown due to concerns about antibiotic resistance and the potential ban on sub-therapeutic antibiotic use. Probiotics, defined as live microbial feed supplements that improve intestinal balance, and prebiotics, which promote the growth of beneficial bacteria, are being explored as alternatives to antibiotics. Studies have shown that probiotics and prebiotics can reduce pathogen colonization, alter microbial populations, and improve immune function. However, the effectiveness of these products can be influenced by environmental and stress factors. Research has focused on identifying beneficial bacterial strains and substrates that enhance resistance to pathogens. The use of competitive exclusion, where 1-day-old chicks are inoculated with adult microbiota, has demonstrated the impact of the intestinal microbiota on disease resistance. Probiotics and prebiotics have been shown to reduce colonization and shedding of pathogens such as Salmonella and Campylobacter. Despite promising results, challenges remain in assessing the efficacy of probiotics due to variability in study designs and environmental factors. Future research should focus on defining the conditions under which these products are effective and understanding their mechanisms of action. As pressure increases to eliminate sub-therapeutic antibiotic use, prebiotics and probiotics show promise as alternatives in poultry production.Prebiotics and probiotics are increasingly used in poultry production to enhance health and reduce the risk of enteric diseases. The intestinal microbiota, epithelium, and immune system work together to resist pathogens. Mechanisms of resistance include competition for colonization sites, nutrient competition, production of toxic compounds, and immune stimulation. Lactic acid bacteria (lactobacilli and bifidobacteria) are believed to improve health through these mechanisms. Research shows that probiotics and prebiotics can increase resistance to disease by modulating the intestinal microbiota and immune system. Prebiotics are non-digestible food ingredients that selectively stimulate the growth of beneficial bacteria, while probiotics are live microorganisms that beneficially affect the host. Synbiotics combine prebiotics and probiotics for enhanced effects. Probiotics and prebiotics have been used for centuries, either as natural components of food or as fermented foods. Interest in their use in poultry has grown due to concerns about antibiotic resistance and the potential ban on sub-therapeutic antibiotic use. Probiotics, defined as live microbial feed supplements that improve intestinal balance, and prebiotics, which promote the growth of beneficial bacteria, are being explored as alternatives to antibiotics. Studies have shown that probiotics and prebiotics can reduce pathogen colonization, alter microbial populations, and improve immune function. However, the effectiveness of these products can be influenced by environmental and stress factors. Research has focused on identifying beneficial bacterial strains and substrates that enhance resistance to pathogens. The use of competitive exclusion, where 1-day-old chicks are inoculated with adult microbiota, has demonstrated the impact of the intestinal microbiota on disease resistance. Probiotics and prebiotics have been shown to reduce colonization and shedding of pathogens such as Salmonella and Campylobacter. Despite promising results, challenges remain in assessing the efficacy of probiotics due to variability in study designs and environmental factors. Future research should focus on defining the conditions under which these products are effective and understanding their mechanisms of action. As pressure increases to eliminate sub-therapeutic antibiotic use, prebiotics and probiotics show promise as alternatives in poultry production.