Phase 3 Study to Evaluate the Safety and Efficacy of Hydrocortisone Acetate Suppositories

Inclusion Criteria: * Male or non pregnant, non lactating females aged 18 years and older. * Able to provide informed consent. * Subjects with a confirmed diagnosis of active UC of the rectum, extending no more than 15 centimeters (cm) (5.9 inches) proximal to the anal verge as assessed by colonoscopy performed at Visit 2. Note: Subjects may have a history of more extensive UC (e.g., pancolitis), but have active disease only in the rectum at the time of enrollment. * Modified Mayo sub score for stool frequency of 1-3. * Modified Mayo sub score for rectal bleeding of 0-2. * Modified Mayo endoscopic sub score of 2-3. * Total Modified Mayo Score (without physician global assessment) of 4-8. Exclusion Criteria: * History or current diagnosis of bacterial or other infectious colitis, radiation enteritis and radiation proctitis, Crohn's disease, collagenous colitis and indeterminate colitis. * Prior gastrointestinal surgery except appendectomy, cholecystectomy, and hernia. * Concomitant active lower gastrointestinal disease (except Irritable Bowel Syndrome) or distortion of intestinal anatomy. * Bleeding hemorrhoids at the time of enrollment. * Acute diverticulitis at the time of enrollment. * Acute or chronic pancreatitis at the time of enrollment. * Unmanaged celiac disease at the time of enrollment. * Positive stool test for enteric pathogens, Clostridium difficile, or presence of ova and parasites. * Taking a prohibited medication.