Brief Summary:

This is a randomized, controlled study evaluating metformin tablets administered daily for 8 weeks. The purpose of the study is to evaluate the efficacy and safety of metformin in the treatment of mild to moderately active ulcerative colitis. Disease activity will be measured using Mayo score for ulcerative colitis activity. Calculation of the score requires patients to undergo colonoscopy at the start of the study and at week 8.

Inclusion Criteria:

1. Patients with mild or moderate ulcerative colitis newly diagnosed by colonoscopy and biopsy according to Mayo endoscopic scoring of ulcerative colitis.
2. Adults (males and/or females) with age range from 18 to 65 years old.
3. Patients on treatment with 5-aminosalisylic acid (5-ASA)

Exclusion Criteria:

1. Patients with severe ulcerative colitis according to Mayo endoscopic scoring of ulcerative colitis.
2. Treatment with systemic or rectal steroids.
3. Treatment with immunosuppressants.
4. Previously failed treatment with a sulphasalazine.
5. Known hypersensitivity to any of study drugs.
6. Hepatic and renal dysfunction.
7. Pregnancy and lactation.
8. History of colorectal carcinoma.
9. History of complete or partial colectomy.
10. Current or previous treatment with metformin for females with polycystic ovarian syndrome.
11. Patients with diabetes mellitus
12. Patients with history of lactic acidosis
13. Patients with disease states associated with hypoxemia including cardiorespiratory insufficiency
14. Positive stool culture for enteric pathogens, positive stool ova and parasite exam.