Transfer of FRozen Encapsulated Multidonor Stool Filtrate for Active Ulcerative COlitis

This study is testing whether transplanting frozen, filtered stool from healthy donors (a fecal microbiota transplant, or FMT) delivered during a colonoscopy can help put ulcerative colitis into remission in patients whose disease has not responded to standard medications. **You may be eligible if...** - You are between 18 and 75 years old - You have been diagnosed with ulcerative colitis (UC) confirmed by colonoscopy at least 6 months ago, affecting at least 15 cm of the colon - Your disease is currently active (moderate flare as measured by the Mayo Score) - Your UC has not responded well to standard treatments (such as 5-ASA, steroids, immunosuppressants, or biologic drugs) - You have been vaccinated against COVID-19 or have had a prior COVID-19 infection - You are on a stable dose of any current UC medications **You may NOT be eligible if...** - Your disease is very severe or involves complications that would make colonoscopy unsafe - You are pregnant or breastfeeding - You have had a recent serious infection or require immune-suppressing treatment - You have not met the minimum activity threshold for current disease Talk to your doctor to see if this trial is right for you.