The gut microbiome is a complex and dynamic ecosystem composed of trillions of microorganismsincluding bacteria, viruses, fungi, and archaearesiding in the gastrointestinal tract. This microbial community contributes significantly to digestion, nutrient absorption, immune regulation, pathogen defense, and neurochemical signaling through the gutbrain axis. A balanced microbiome supports optimal physiological functioningwhile disturbancesreferred to as dysbiosisare associated with numerous disordersincluding obesity, inflammatory bowel disease (IBD)allergiesautoimmune conditionsneuropsychiatric disordersand colorectal cancer. Microbiome composition is shaped by various factors such as dietantibiotic exposurebirth modeagingstressand physical activity. Understanding these interactions provides opportunities for therapeutic interventions, including dietary modulationprobioticsprebioticsfecal microbiota transplantation (FMT)and emerging personalized microbiome-targeted strategies. This review summarizes the core functions of the gut microbiomeits role in disease pathogenesisand current evidence-based approaches to maintaining or restoring microbial balance.