Fecal Microbiota Transplantation: A Promising Therapeutic Strategy Targeting the Microbiota–Gut–Brain Axis in Anorexia Nervosa

PURPOSE: Anorexia nervosa (AN) is a complex psychiatric disorder characterized by self-starvation, body-image disturbance, and serious medical complications. Because current treatments have variable outcomes and relapse is common, the microbiota-gut-brain axis has been investigated as a possible contributor to disease persistence. This review evaluates fecal microbiota transplantation (FMT) as an experimental microbiota-directed strategy for AN. METHODS: PubMed, Embase, Scopus, and Google Scholar were searched for relevant studies published from January 1990 to October 2025. Eligible evidence included human reports, animal studies, and mechanistic studies examining FMT or gut-microbiota alterations in AN and related pathways. FINDINGS: Individuals with AN have been reported to show altered microbial diversity and changes in taxa associated with short-chain fatty acid production and inflammation. These findings are heterogeneous and may reflect starvation, diet, medication exposure, or illness-related physiology. Human evidence for FMT in AN is limited to small, uncontrolled studies and case reports, while most mechanistic support comes from animal models or indirect evidence from other conditions. CONCLUSION: Evidence for FMT in AN remains preliminary and is largely based on uncontrolled human observations and preclinical studies. FMT may alter gut microbial composition and gastrointestinal or metabolic measures, but controlled efficacy data are absent and psychiatric benefits remain unconfirmed. Well-designed controlled trials are needed to establish its safety and clinical efficacy.