• The primary efficacy endpoint is the proportion of subjects that achieve clinical improvement and improvement in the rectal bleeding subscale of the MMDAI at the end of six weeks of therapy.
  

Inclusion Criteria:

• mildly to moderately active ulcerative colitis.
• disease extends at least 20 cm from the rectum.
• baseline MMDAI score between 6-10, inclusive, and greater than or equal to 2 on the MMDAI bleeding component and endoscopy/sigmoidoscopy component.
• not taking more than 4.8 grams/day of Asacol, greater than or equal to 6.75 grams/day of Colazal,or 2.4 grams/day of mesalamine or equivalent daily dose using any other 5-ASA products at any time during the 14 days preceding the initiation of study medication.
• if of childbearing potential, negative serum pregnancy test.

Exclusion Criteria:

• subject has a significant medical, including psychiatric, condition which in the opinion of the investigator precludes participation in the study.
• subject has a history of allergy or intolerance to aspirin, mesalamine, or other salicylates.
• subject's UC has worsened or failed to improve during chronic (i.e., at least 7) therapy with greater than or equal to 6.6 g/day days of balsalazide disodium within 30 days of screening
• subject has received chronic (i.e., greater than 15 consecutive days) of immunosuppressive therapy (e.g. azathioprine, 6 mercaptopurine) or corticosteroids within 30 days of screening. Intermittent use of oral or rectal immunosuppressive therapy or corticosteroids within 30 days of screening is permitted. Intravenous use of corticosteroids within 30 days of screening is not permitted.
• subject has received intra-rectal aminosalicylates for greater than 2 consecutive days within 7 days of screening.
• subject has had any prior bowel surgery, except appendectomy or cholecystectomy.
• subject has participated in an investigational drug or device study within the 30 days prior to study.
• subject is pregnant or at risk of pregnancy, or is lactating (female subjects only).
• subject shows evidence of current excessive alcohol consumption or drug dependence.
• subject has a history of human immunodeficiency virus (HIV). Subjects with history of hepatitis B and C will be eligible provided the screening LFTs are within normal limits.
• subject has other infectious, ischemic, or immunologic diseases with GI involvement.
• subject has twice the upper limit of normal (ULN) for any of the following LFTs: alanine aminotransferase (ALT/SGPT), aspartate aminotransferase (AST/SGOT), alkaline phosphatase, or total bilirubin (except isolated elevation of unconjugated bilirubin).
• subject has uncontrolled, clinically significant renal disease manifested by 1.5 × ULN of serum creatinine.
• subject has calculated creatinine clearance level of less than or equal to 60 mL/min.
• subject has unstable cardiovascular, coagulopathy or pulmonary disease characterized by a worsening in the disease condition that required a change in treatment or medical care within one (1) month of randomization.
• subject has active malignancy within the last 5 years, except basal cell carcinoma of the skin, or if female, in situ cervical carcinoma that has been surgically excised.
• subject has any condition or circumstance that would, in the opinion of the investigator, prevent completion of the study or interfere with analysis of study results, including history of noncompliance with treatments or visits.
• subject has sclerosing cholangitis.
• subject has positive stool culture for ovum and parasites (O&P) or C. difficile.
• subject has been treated with infliximab, cyclosporine, natalizumab, or methotrexate for ulcerative colitis within the last 30 days prior to screening.
• regular use of NSAIDS except cardioprotective ASA (i.e., less than or equal to 162 mg ASA per day).
• subject has received cell-depleting therapies such as the Adacolumn.
• subject requires antidiarrheal therapy during screening.
• subject has clinical or radiographic findings suggestive of serious UC complications such as toxic megacolon or colonic perforation.