The article reviews the role of the normal gut microbiota in human health, emphasizing its functional implications and the mechanisms that orchestrate these functions. The gut microbiota, primarily composed of Bacteroidetes and Firmicutes, plays a crucial role in nutrient metabolism, xenobiotic and drug metabolism, maintaining the structural integrity of the gut mucosal barrier, immunomodulation, and protection against pathogens. Factors such as mode of delivery, diet, and antibiotic use significantly shape the gut microbiota. The article discusses the challenges in studying the gut microbiota, including the use of high-throughput sequencing technologies and bioinformatics analysis. It highlights the importance of understanding the gut microbiota's composition, diversity, and functions, particularly in maintaining health and preventing diseases. The review also explores the impact of diet, antibiotics, probiotics, prebiotics, and synbiotics on the gut microbiota, emphasizing the need for caution in antibiotic use to prevent long-term alterations and the spread of antibiotic resistance genes.The article reviews the role of the normal gut microbiota in human health, emphasizing its functional implications and the mechanisms that orchestrate these functions. The gut microbiota, primarily composed of Bacteroidetes and Firmicutes, plays a crucial role in nutrient metabolism, xenobiotic and drug metabolism, maintaining the structural integrity of the gut mucosal barrier, immunomodulation, and protection against pathogens. Factors such as mode of delivery, diet, and antibiotic use significantly shape the gut microbiota. The article discusses the challenges in studying the gut microbiota, including the use of high-throughput sequencing technologies and bioinformatics analysis. It highlights the importance of understanding the gut microbiota's composition, diversity, and functions, particularly in maintaining health and preventing diseases. The review also explores the impact of diet, antibiotics, probiotics, prebiotics, and synbiotics on the gut microbiota, emphasizing the need for caution in antibiotic use to prevent long-term alterations and the spread of antibiotic resistance genes.