The article discusses the role of the vagus nerve (VN) in the microbiota-gut-brain axis, a bidirectional communication pathway involving the autonomic nervous system. The VN, composed of 80% afferent and 20% efferent fibers, plays a crucial role in sensing and integrating gut microbiota signals into the central nervous system. A cholinergic anti-inflammatory pathway through the VN's fibers can dampen peripheral inflammation and reduce intestinal permeability, potentially modulating microbiota composition. Stress inhibits the VN and has detrimental effects on the gastrointestinal tract and microbiota, contributing to conditions like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Low vagal tone is observed in IBD and IBS patients, favoring peripheral inflammation. Targeting the VN, such as through VN stimulation (VNS), which has anti-inflammatory properties, could restore homeostasis in these diseases. The article also highlights the involvement of gut endocrine cells and the central autonomic network in the VN's role in the microbiota-gut-brain axis.The article discusses the role of the vagus nerve (VN) in the microbiota-gut-brain axis, a bidirectional communication pathway involving the autonomic nervous system. The VN, composed of 80% afferent and 20% efferent fibers, plays a crucial role in sensing and integrating gut microbiota signals into the central nervous system. A cholinergic anti-inflammatory pathway through the VN's fibers can dampen peripheral inflammation and reduce intestinal permeability, potentially modulating microbiota composition. Stress inhibits the VN and has detrimental effects on the gastrointestinal tract and microbiota, contributing to conditions like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Low vagal tone is observed in IBD and IBS patients, favoring peripheral inflammation. Targeting the VN, such as through VN stimulation (VNS), which has anti-inflammatory properties, could restore homeostasis in these diseases. The article also highlights the involvement of gut endocrine cells and the central autonomic network in the VN's role in the microbiota-gut-brain axis.