1. Adults, male and female, 18 to 65 years of age 2. Active, mild to moderate UP, with disease activity not to exceed 15 cm beyond the anal verge: the upper disease boundary will be confirmed by flexible sigmoidoscopy/colonoscopy performed within 14 days of the Baseline Visit 3. Newly diagnosed or newly relapsed UP, where newly relapsed UP is defined as UP that has relapsed within less than and equal to 6 weeks prior to the Baseline Visit 4. A Disease Activity Index (DAI) score greater than or equal to 4 and less than or equal to 10 at the Baseline Visit; the DAI must include a Physician's Global Assessment (PGA) sub-score of less than or equal to 2, a rectal bleeding sub-score of greater than or equal to 1 and a mucosal appearance sub-score of greater than or equal to 1 5. Histological confirmation of UP with a Histological Disease Activity Score > or equal to 1 for the biopsy taken from the most severe area of disease during the flexible sigmoidoscopy/colonoscopy performed within 14 days of the Baseline Visit 6. For female patients of child-bearing potential, a negative serum pregnancy test at the Screening Visit and a negative urine pregnancy test at the Baseline Visit; all female patients will be considered of child-bearing potential unless they are post-menopausal for at least one year or have been surgically sterilized (bilateral tubal ligation, bilateral oophorectomy, or hysterectomy) 7. Female patients of childbearing potential must be practicing one of the following methods of birth control and must agree to continue with regimen throughout the study: hormonal methods such as oral, implantable, injectable, or transdermal contraceptives for a minimum of one full cycle (based on the patient's usual menstrual cycle period) before investigational product administration; total abstinence from sexual intercourse (since the last menses before investigational product administration); intrauterine device; double barrier method (condoms, sponge, diaphragm, or vaginal ring with spermicidal jellies or cream); Male patients must also agree to use acceptable methods of birth control with their female partners, and this may include use of a male condom plus spermicide. 8. Ability to give written informed consent 9. Ability and willingness to comply with study requirements, including dosing procedures, diary completion, and study visits