BACKGROUND AND OBJECTIVE: Colonic dysbiosis contributes to the development of colonic inflammation in ulcerative colitis (UC). Fecal microbial transplantation (FMT) is being proposed as a novel treatment for UC because it can eliminate dysbiosis; however, no prospective data exist. We initiated a pilot study to evaluate feasibility and safety of FMT in children with UC. METHODS: Ten children, 7 to 21 years of age, with mild-to-moderate UC (pediatric UC activity index [PUCAI] between 15 and 65) received freshly prepared fecal enemas daily for 5 days. Data on tolerability, adverse events, and disease activity were collected during FMT and weekly for 4 weeks after FMT. Clinical response was defined as decrease in PUCAI by >15, and decrease in PUCAI to <10 was considered clinical remission. RESULTS: No serious adverse events were noted. Mild (cramping, fullness, flatulence, bloating, diarrhea, and blood in stool) to moderate (fever) adverse events were self-limiting. One subject could not retain fecal enemas. Average tolerated enema volume by remaining 9 subjects was 165 mL/day. After FMT, 7 of the 9 (78%) subjects showed clinical response within 1 week, 6 of the 9 (67%) subjects maintained clinical response at 1 month, and 3 of the 9 (33%) subjects achieved clinical remission at 1 week after FMT. Median PUCAI significantly improved after FMT (P = 0.03) compared with the baseline. CONCLUSIONS: Fecal enemas were feasible and tolerated by children with UC. Adverse events were acceptable, self-limiting, and manageable by subjects. FMT indicated efficacy in the treatment of UC.