Once Daily (OD) Versus Three Times Daily (TID) Dosing With Mesalazine Granules for Prevention of Recurrence of Ulcerative Colitis (UC)

Inclusion Criteria: * Signed informed consent, * Men or women aged 18 to 75 years, * Historically confirmed diagnosis of ulcerative colitis by endoscopy and histology, * Patient being in remission, defined (according to Rachmilewitz) as: Clinical Activity Index (CAI) \<= 4, and Endoscopic Index (EI) \< 4, * Extent of inflammation during last acute episode was \>15 cm beyond the anal margin, * Last acute episode ended within 3 months prior to study entry. Exclusion Criteria: * Crohn's disease, * Prior bowel resection leading to diarrhoea, * Toxic megacolon, * Gastric or duodenal ulcer, * Haemorrhagic diathesis, * Presence of symptomatic organic disease of the gastrointestinal tract (with the exception of haemorrhoids or hiatal hernia), * Active colorectal cancer or a history of colorectal cancer, * Serious other secondary illnesses of an acute or chronic nature, * Asthma, * Severe impairment of renal (e.g., serum creatinine \> 1.5 mg/dl) and/or liver functions (e.g., serum transaminase \[ALT and/or AST\] or alkaline phosphatase \>=2x upper limit of normal \[ULN\]), * Application of immunosuppressants within 3 months and/or corticosteroids (oral, intravenous \[IV\] or topical rectal) within 30 days prior to baseline, * Application of non-steroidal anti-inflammatory drugs (NSAIDs) as long term treatment (i.e. \> 6 weeks), other than acetylsalicylic acid (\<= 350 mg/day), or paracetamol, * Known intolerance/hypersensitivity to salicylic acid and its derivatives or to any of the other constituents of the study drugs, * Well-founded doubt about the patient's cooperation, * Existing or intended pregnancy, breast-feeding, * Women of child-bearing potential without adequate contraceptive protection, e.g., hormonal contraception, intrauterine device (IUD), double-barrier method of contraception (e.g., use of a condom and spermicide), partner has undergone vasectomy and subject is in monogamous relationship. The investigator is responsible for determining whether the subject has adequate birth control for study participation, * Participation in another clinical trial within the last 30 days,simultaneous participation in another clinical trial, or previous participation in this trial.