Fecal Microbiota Transplantation in Inflammatory Bowel Disease: A Systematic Review of Efficacy and Safety

Inflammatory bowel disease (IBD), comprising ulcerative colitis (UC) and Crohn's disease (CD), is a chronic inflammatory condition of the gastrointestinal tract associated with immune dysregulation and alterations in the gut microbiota. Growing evidence suggests that intestinal microbial dysbiosis plays an important role in disease pathogenesis, prompting interest in microbiome-targeted therapies, such as fecal microbiota transplantation (FMT). This systematic review aimed to evaluate the efficacy and safety of FMT in adult patients with IBD. A comprehensive literature search was conducted in PubMed, Embase, Scopus, and the Cochrane Library for studies published between 2020 and 2025 using keywords related to "fecal microbiota transplantation" and "inflammatory bowel disease." Eligible studies included randomized controlled trials (RCTs), cohort studies, systematic reviews, and meta-analyses involving adult patients with UC or CD. Due to clinical and methodological heterogeneity, a structured narrative synthesis was performed in accordance with Synthesis Without Meta-analysis (SWiM) guidelines. Nine studies comprising 1,847 participants met the inclusion criteria, including five RCTs, two systematic reviews, and two meta-analyses. In patients with UC, clinical remission rates ranged from 32% to 40%, with response rates between 44% and 52%. In CD, remission rates ranged from 24% to 31%, although evidence remained limited and heterogeneous. Multi-donor stool preparations and repeated FMT administrations were associated with improved clinical outcomes compared with single-donor protocols or single-dose protocols. Adverse events occurred in approximately 12-15% of patients and were predominantly mild gastrointestinal symptoms, while serious adverse events were rare (<2%). Current evidence suggests that FMT may induce clinical remission in a subset of patients with UC, while evidence in CD remains less consistent. Larger randomized trials with standardized protocols and long-term follow-up are needed to determine optimal donor selection, dosing strategies, and long-term safety.