Environmental and chemical contaminants from industrial and agricultural sources increasingly threaten food safety worldwide. These contaminants, including bacterial toxins (e.g., botulinum toxin), mycotoxins (e.g., aflatoxin, ochratoxin), pesticides, heavy metals, and microplastics, pose significant health and economic risks. Emerging evidence highlights that chronic exposure to such xenobiotics disrupts gut microbiota structure and function, adversely affecting host health. While traditional physicochemical detoxification methods exist, they often require impractical conditions. Biological detoxification via probiotics and their metabolites (postbiotics) has gained attention as a practical and cost-effective alternative. Numerous studies concur that probiotics can bind, biotransform, or sequester xenobiotics, thereby mitigating toxicity and restoring microbiota balance. However, variations in strain efficacy, binding mechanisms, and in vivo performance indicate areas needing further exploration. This review critically synthesizes current knowledge on probiotic-mediated detoxification mechanisms, their interaction with xenobiotics and the gut microbiome, and host responses, highlighting consensus, discrepancies, and gaps to inform future research and applications.