Gut microbiota or microbiome is the sum of microorganisms found in the digestive system, especially the large intestine. These microorganisms include bacteria, viruses, fungi and other microscopic organisms. The gut microbiota has a significant impact on human health and contributes to many important functions. The gut microbiota helps digest and absorb nutrients. It plays an important role in metabolizing some nutrients, especially fibrous foods. Additionally, some types of microbiota can help produce some vitamins essential for the body. A healthy and balanced intestinal microbiota supports the development and function of the immune system, regulates immune responses and plays a protective role against diseases. It is thought that there is a connection between the gut microbiota and the brain. Imbalances in the microbiota have been linked to depression, anxiety and other mental health problems. A healthy microbiota can reduce inflammation and the risk of inflammatory diseases in the body. An unbalanced microbiota can lead to digestive system disorders such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and contribute to the development of metabolic diseases such as obesity and diabetes. For these reasons, maintaining or rebalancing a healthy gut microbiota is important for overall health. Strategies such as a balanced diet, consumption of fibrous foods, and use of probiotics and prebiotics can help support a healthy gut microbiota.