Shahrekord University of Medical Sciences Journal of Shahrekord University of Medical Sciences 2717-0071 28 2 2026 07 29 Compositional and Functional Diversity of Microbiota in Human Diseases 104 111 10.34172/jsums.1082 EN Majid Validi https://orcid.org/0000-0001-8023-0620 Mansoor Khaledi https://orcid.org/0000-0002-1576-5968 Journal Article 10.34172/jsums.1082 2025 10 01 2025 11 01 Introduction: The microbes residing in the intestines, referred to as the intestinal microbiota, play a crucial role in energy metabolism, normal body function, immune system regulation, obesity, malnutrition, neurological conditions, mood, behavior, and various diseases, particularly intestinal disorders and cancer. This mini-review summarizes the compositional and functional diversity of the microbiota in relation to human diseases. Methods: We searched published studies across several electronic databases, including ScienceDirect, PubMed, PubMed Central (PMC), Scopus, Google Scholar, ISI Web of Science, Medlib, Magiran, the Iranian Scientific Information Database (SID), and IranMedex. Results: The intestinal microbiota is associated with a broad range of human health conditions, including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), obesity, diabetes, allergic disorders, colon cancer, cardiovascular disease (CVD), and type 2 diabetes (T2D). Moreover, the intestinal microbiota influences the functioning of the central nervous system through the intestinal nervous system, production of metabolites, stimulation of enteroendocrine cells, and modulation of the immune system. Conclusion: There is a complex interplay between the gut microbiota and overall human health, with imbalances in gut microbiome composition associated with gastrointestinal disorders, metabolic diseases, neurological disorders, and immune-related disorders.