The gut-brain axis (GBA) is a bidirectional communication system between the central nervous system (CNS) and the enteric nervous system (ENS), linking brain functions with intestinal activities. Recent research highlights the role of gut microbiota in influencing this interaction through neural, endocrine, immune, and humoral pathways. The gut microbiota, primarily composed of Firmicutes and Bacteroides, plays a crucial role in maintaining host homeostasis and affects brain functions such as emotion, motivation, and cognition. Dysbiosis, or imbalance in gut microbiota, is associated with central nervous system disorders like autism, anxiety, and depression, as well as functional gastrointestinal disorders, including irritable bowel syndrome (IBS). IBS is considered a disorder of the microbiome-GBA, with evidence showing that gut microbiota can influence intestinal motility, secretion, and immune responses. Probiotics and antibiotics have been shown to modulate gut microbiota and alleviate symptoms in IBS patients. The gut microbiota also interacts with the brain through the vagus nerve, influencing stress responses and emotional behavior. Additionally, microbiota can affect the brain via the modulation of the intestinal barrier, neurotransmitter systems, and immune responses. Stress can alter the composition of the gut microbiota, which in turn affects brain function and gut health. The interaction between the brain and gut microbiota is complex, involving multiple pathways, and is influenced by factors such as diet, stress, and microbial composition. Understanding these interactions may lead to new therapeutic strategies for neurological and gastrointestinal disorders.The gut-brain axis (GBA) is a bidirectional communication system between the central nervous system (CNS) and the enteric nervous system (ENS), linking brain functions with intestinal activities. Recent research highlights the role of gut microbiota in influencing this interaction through neural, endocrine, immune, and humoral pathways. The gut microbiota, primarily composed of Firmicutes and Bacteroides, plays a crucial role in maintaining host homeostasis and affects brain functions such as emotion, motivation, and cognition. Dysbiosis, or imbalance in gut microbiota, is associated with central nervous system disorders like autism, anxiety, and depression, as well as functional gastrointestinal disorders, including irritable bowel syndrome (IBS). IBS is considered a disorder of the microbiome-GBA, with evidence showing that gut microbiota can influence intestinal motility, secretion, and immune responses. Probiotics and antibiotics have been shown to modulate gut microbiota and alleviate symptoms in IBS patients. The gut microbiota also interacts with the brain through the vagus nerve, influencing stress responses and emotional behavior. Additionally, microbiota can affect the brain via the modulation of the intestinal barrier, neurotransmitter systems, and immune responses. Stress can alter the composition of the gut microbiota, which in turn affects brain function and gut health. The interaction between the brain and gut microbiota is complex, involving multiple pathways, and is influenced by factors such as diet, stress, and microbial composition. Understanding these interactions may lead to new therapeutic strategies for neurological and gastrointestinal disorders.