The human gut microbiota is increasingly studied due to its association with various diseases, including metabolic disorders, autoimmune diseases, cancer, and neurodevelopmental disorders. Mice are widely used as a model system for gut microbiota research due to their anatomical, physiological, and genetic similarities to humans. However, translating findings from mouse models to humans requires careful consideration of intrinsic and extrinsic differences between the two systems. The anatomy of the mouse and human gastrointestinal tracts is similar, but there are notable differences. For example, the mouse cecum is larger relative to its total gastrointestinal tract and plays a significant role in fermentation and vitamin production. In contrast, the human cecum is smaller and has a different anatomical structure. The mouse colon is smooth, while the human colon is segmented into pouches called haustra. These anatomical differences may influence the composition and diversity of gut microbiota in the colon. The gut microbiota composition in healthy humans and mice is dominated by Bacteroidetes and Firmicutes. However, there are significant differences in the genera present in the two systems. For example, Prevotella, Faecalibacterium, and Ruminococcus are more abundant in human gut microbiota, while Lactobacillus, Alistipes, and Turicibacter are more abundant in mice. Despite these differences, some genera are shared between the two systems, and the core gut microbiota of both species is relatively similar. In terms of disease, the gut microbiota shifts associated with obesity and inflammatory bowel disease (IBD) are similar in mice and humans. However, there are discrepancies in the extent to which these shifts are observed, possibly due to differences in diet, genetic background, and environmental factors. For example, in mouse studies, the Firmicutes:Bacteroidetes ratio is often increased in obese mice, similar to what is observed in some human studies. However, other studies have reported conflicting results, suggesting that the ratio may not be a reliable indicator of microbiota changes associated with obesity. The composition of the gut microbiota is also influenced by environmental factors, including housing conditions and diet. Mice housed in clean facilities, such as SPF conditions, may have a different microbiota composition compared to wild mice. Additionally, the diet of laboratory mice, which is typically a standardized chow diet, may differ significantly from the diet of humans, potentially affecting the composition of the gut microbiota. In conclusion, while mouse models are valuable tools for studying the gut microbiota, there are important differences between the two systems that must be considered when translating findings from mouse models to humans. These differences include anatomical, genetic, and environmental factors that can influence the composition and diversity of the gut microbiota. Therefore, careful consideration of these factors is essential when using mouse models for gut microbiota research.The human gut microbiota is increasingly studied due to its association with various diseases, including metabolic disorders, autoimmune diseases, cancer, and neurodevelopmental disorders. Mice are widely used as a model system for gut microbiota research due to their anatomical, physiological, and genetic similarities to humans. However, translating findings from mouse models to humans requires careful consideration of intrinsic and extrinsic differences between the two systems. The anatomy of the mouse and human gastrointestinal tracts is similar, but there are notable differences. For example, the mouse cecum is larger relative to its total gastrointestinal tract and plays a significant role in fermentation and vitamin production. In contrast, the human cecum is smaller and has a different anatomical structure. The mouse colon is smooth, while the human colon is segmented into pouches called haustra. These anatomical differences may influence the composition and diversity of gut microbiota in the colon. The gut microbiota composition in healthy humans and mice is dominated by Bacteroidetes and Firmicutes. However, there are significant differences in the genera present in the two systems. For example, Prevotella, Faecalibacterium, and Ruminococcus are more abundant in human gut microbiota, while Lactobacillus, Alistipes, and Turicibacter are more abundant in mice. Despite these differences, some genera are shared between the two systems, and the core gut microbiota of both species is relatively similar. In terms of disease, the gut microbiota shifts associated with obesity and inflammatory bowel disease (IBD) are similar in mice and humans. However, there are discrepancies in the extent to which these shifts are observed, possibly due to differences in diet, genetic background, and environmental factors. For example, in mouse studies, the Firmicutes:Bacteroidetes ratio is often increased in obese mice, similar to what is observed in some human studies. However, other studies have reported conflicting results, suggesting that the ratio may not be a reliable indicator of microbiota changes associated with obesity. The composition of the gut microbiota is also influenced by environmental factors, including housing conditions and diet. Mice housed in clean facilities, such as SPF conditions, may have a different microbiota composition compared to wild mice. Additionally, the diet of laboratory mice, which is typically a standardized chow diet, may differ significantly from the diet of humans, potentially affecting the composition of the gut microbiota. In conclusion, while mouse models are valuable tools for studying the gut microbiota, there are important differences between the two systems that must be considered when translating findings from mouse models to humans. These differences include anatomical, genetic, and environmental factors that can influence the composition and diversity of the gut microbiota. Therefore, careful consideration of these factors is essential when using mouse models for gut microbiota research.