Recent advances have increased the understanding that dysbiosis of the gut microbiome may be a significant contributor to the pathophysiology of ulcerative colitis. Because of this, the use of fecal microbiota transplants (FMT) has become more popular as a potential supplemental treatment option for patients suffering from this disease. Research has shown a possible benefit of FMT in conjunction with varying conventional therapies for patients with mild to moderate disease severity. However, there are scarce publications that have investigated the benefit of FMT in conjunction with a single conventional therapy for patients with moderate to severe disease, specifically. The proposed study is a multicenter, double blind, randomized controlled study of FMT, mercaptopurine (6-MP), and prednisone vs 6-MP and prednisone alone in patients with moderate to severe ulcerative colitis. The study subjects will have a baseline evaluation and the treatment trial will last 8 weeks with follow up throughout the study. Investigators will analyze the primary outcome of clinical remission and secondary outcomes of improvement of fecal calprotectin levels, Inflammatory Bowel Disease Questionnaire (IBDQ) score, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in the treatment vs control groups. The data from this study will help to identify if FMT would be an additional safe, efficacious treatment modality to the current medical management of ulcerative colitis.