As an important intestinal microorganism, Odoribacter splanchnicus frequently appears in high-throughput sequencing analyses, although pure culture research on this microorganism is not as advanced. It is widely present in the mammalian gut and is closely associated with the health status of the host and the incidence of various diseases. In recent years, changes in the abundance of O. splanchnicus have been found to be positively or negatively correlated with health issues, such as obesity, metabolic syndrome, diabetes, and intestinal inflammation. It may exhibit a dual protective or promotional role in specific diseases. Thus, it may play an important role in regulating host metabolism, immune response, and intestinal homeostasis. Additional research has revealed that O. splanchnicus can synthesize various metabolites, especially short-chain fatty acids (SCFAs), which play a key role in promoting intestinal health, enhancing energy metabolism, improving insulin resistance, and regulating immune responses in the host. Therefore, O. splanchnicus is a strong candidate for “next-generation probiotics”, and its potential probiotic function provides novel ideas for the development of functional foods and the prevention and treatment of metabolic and intestinal inflammatory diseases. These findings can help develop new biological treatment strategies and optimize health management plans.

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is considered significant global health concerns worldwide. Many studies have demonstrated that environmental and dietary factors influence the gut microbiota, which in turn orchestrates the host immune responses. These interactions are also involved in complex metabolic processes that contribute to the pathogenesis of IBD. Furthermore, recent studies in genomics and metabolomics have unveiled the intricate relationship between microbial influencers and host epigenetics. The dynamics of gut microbiota and its metabolites intricately align with DNA methylation, histone methylation, lactylation, glycosylation, and non-coding RNAs, which are key players in epigenetics. Here, we summarize and discuss the complex interplay among gut microbiota, epigenetics, and environmental and dietary factors, and their impact on the pathogenesis of IBD. Furthermore, we highlight the importance of multi-omics technologies in dissecting the host-microbe interactions in IBD, potentially offering a framework for developing effective treatment strategies.