The purpose of the study is to obtain a first clinical assessment of the safety of dersalazine sodium in ulcerative colitis patients with mild to moderate disease.

Inclusion Criteria:

• Age 18 to 65 inclusive
• Male, non-child-bearing female or fertile female with appropriate contraception.
• Mild to moderate confirmed active ulcerative colitis
• Able and willing to give informed consent

Exclusion Criteria:

• Colitis of other cause
• Pregnancy, inadequate contraception for fertile female patients
• Liver or kidney disease, unstable cardiovascular disease, coagulation disorder.
• Other significant medical condition that preclude participation at investigator criteria
• Allergy or hypersensitivity to salicylates
• Previous or concomitant treatment for ulcerative colitis interfering with safety or activity assessments