Mesalamine extended-release capsules (Apriso [Salix Pharmaceuticals, Raleigh, NC, USA]) are the first once-daily mesalamine preparation approved by the US FDA for the maintenance of remission of ulcerative colitis (UC). Each mesalamine extended-release capsule contains granules of a mesalamine-polymer matrix that are coated with a pH-sensitive resin. This design begins releasing mesalamine (0.375 g) once the pH is more than 6 in the ileum and colon. Two clinical trials have reported that mesalamine extended-release capsules (1.5 g/day) maintained remission in 79% of patients with UC who were in clinical remission. Reported adherence with mesalamine extended-release capsules once daily was high (>90%) in these studies. This article examines the efficacy and safety of mesalamine extended-release capsules in the maintenance of remission in patients with UC.