With advancing analytical methods for gut microbes, many studies have been conducted, revealing that gut microbes cause various diseases, including gastrointestinal and non-gastrointestinal diseases. Accordingly, studies have been actively conducted to analyze the effects on the prevention and treatment of these diseases through changes in intestinal microbes and control of dysbiosis. Fecal microbiota transplantation (FMT) is an effort and is currently being applied to Clostridioides difficile treatment in Korea. Many studies have demonstrated the application of FMT in inflammatory bowel disease, irritable bowel syndrome, non-alcoholic fatty liver disease, metabolic syndrome, obesity, and diabetes. With further studies and accumulation of evidence, FMT could help treat presently untreatable diseases in clinical practice.