LFMT vs Placebo in New Biologic Start for Ulcerative Colitis

Inclusion Criteria: 1. 18 years of age or older but less than 75 years of age 2. Able to provide informed consent 3. Established ulcerative colitis diagnosis determined by a physician through standard endoscopic and histologic criteria 4. Active UC defined as total Mayo score between 6-12 AND Mayo endoscopic sub-score \>1 with disease that extends 15 cm or more from the anal verge 5. Selected by treating physician for initiation of biologic treatment with either vedolizumab or ustekinumab. Patients must be: * Biologic naive; OR * Have failed anti-TNF, anti-integrin, anti IL12/23 or oral small molecules 6. Use of effective contraception method for women of childbearing potential for at least 4 weeks prior to receiving study treatment and for the duration of the trial 7. Willing and able to comply with all required study procedures Exclusion Criteria: 1. Severe UC requiring hospitalization 2. Indeterminate colitis 3. Evidence of or treatment for C difficile infection or other intestinal pathogen, including CMV, within 4 weeks prior to enrollment 4. Evidence of toxic megacolon or gastrointestinal perforation on imaging 5. Abdominal surgery within the past 60 days * Neutropenia with absolute neutrophil count \<0.5 x 109/L * Peripheral white blood cell count \> 35.0 x 109/L and fever (\>38 degrees Celsius) * Planned or actively taking another investigational product * Uncontrolled medical conditions such as psychiatric disorders or substance abuse * Severe underlying disease such that the patient is not expected to survive for at least 30 days 6. Pregnant or lactating 7. Unwilling to discontinue non-dietary probiotic 8. Antibiotic use in the past 30 days or anticipated need for systemic antibiotic use during study 9. FMT within 3 months prior to enrollment 10. Use of the following medications: 1. rectal/topical therapy within 2 weeks of screening 2. cyclosporine, tacrolimus or thalidomide within 4 weeks of screening 3. tofacitinib within 4 weeks of screening 4. adalimumab or infliximab within 8 weeks of screening 5. vedolizumab within 8 weeks of screening 6. ustekinumab within 12 weeks of screening 7. prednisone \> 30 mg/d 11. Investigator deems enrolment in the study is not in the best interest of the patient