Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is a chronic, relapsing inflammatory disorder of the intestine. The exact cause of IBD remains unclear, but it is believed to result from complex interactions between genetics, environmental factors, and the host immune system. The gut microbiota, a complex community of microbes, plays a crucial role in maintaining host health by contributing to nutrition, immune function, and defense against pathogens. Recent studies have shown that alterations in the gut microbiota, known as dysbiosis, are associated with IBD. Dysbiosis is characterized by reduced microbial diversity, decreased production of short-chain fatty acids (SCFAs), and increased presence of pathogenic bacteria. These changes disrupt the host-microbiota interaction and immune system, leading to chronic inflammation and aberrant immune responses. The gut microbiota influences immune system development, T-cell repertoires, and the balance of T-helper cells. It also enhances host defense by promoting colonization resistance, producing antimicrobial factors, and modulating the immune response. In IBD, the microbiota is altered, with a decrease in anti-inflammatory bacteria and an increase in pro-inflammatory bacteria. This dysbiosis is linked to the pathogenesis of IBD, although a direct causal relationship has not been established. Therapeutic strategies targeting the gut microbiota include probiotics and fecal microbiota transplantation (FMT). Probiotics, such as Lactobacillus and Bifidobacterium, have shown some efficacy in reducing inflammation in IBD patients. FMT has been effective in treating recurrent Clostridium difficile infection but its efficacy in IBD is still under investigation. Clinical trials have shown mixed results, with some studies indicating that FMT can induce remission in IBD patients, while others have found no significant benefit. Factors such as donor selection, disease state, and treatment protocol influence the effectiveness of FMT. Future research is needed to optimize FMT protocols and determine its long-term safety and efficacy in IBD. Advances in understanding the gut microbiota and its interactions with the host are expected to lead to new therapeutic strategies for IBD.Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is a chronic, relapsing inflammatory disorder of the intestine. The exact cause of IBD remains unclear, but it is believed to result from complex interactions between genetics, environmental factors, and the host immune system. The gut microbiota, a complex community of microbes, plays a crucial role in maintaining host health by contributing to nutrition, immune function, and defense against pathogens. Recent studies have shown that alterations in the gut microbiota, known as dysbiosis, are associated with IBD. Dysbiosis is characterized by reduced microbial diversity, decreased production of short-chain fatty acids (SCFAs), and increased presence of pathogenic bacteria. These changes disrupt the host-microbiota interaction and immune system, leading to chronic inflammation and aberrant immune responses. The gut microbiota influences immune system development, T-cell repertoires, and the balance of T-helper cells. It also enhances host defense by promoting colonization resistance, producing antimicrobial factors, and modulating the immune response. In IBD, the microbiota is altered, with a decrease in anti-inflammatory bacteria and an increase in pro-inflammatory bacteria. This dysbiosis is linked to the pathogenesis of IBD, although a direct causal relationship has not been established. Therapeutic strategies targeting the gut microbiota include probiotics and fecal microbiota transplantation (FMT). Probiotics, such as Lactobacillus and Bifidobacterium, have shown some efficacy in reducing inflammation in IBD patients. FMT has been effective in treating recurrent Clostridium difficile infection but its efficacy in IBD is still under investigation. Clinical trials have shown mixed results, with some studies indicating that FMT can induce remission in IBD patients, while others have found no significant benefit. Factors such as donor selection, disease state, and treatment protocol influence the effectiveness of FMT. Future research is needed to optimize FMT protocols and determine its long-term safety and efficacy in IBD. Advances in understanding the gut microbiota and its interactions with the host are expected to lead to new therapeutic strategies for IBD.