First-line therapies in the treatment of patients with mild-to-moderate ulcerative colitis are sulfasalazine or one of the mesalamine derivatives. Mesalamine is popular given its safety profile and reasonable efficacy in many patients. However, compliance is poor with regimens demanding large number of pills dosed multiple times a day and non-compliance has been correlated with disease relapse. Mesalamine requires direct contact with the inflamed colonic mucosa. To avoid proximal absorption, a variety of delivery systems has been utilized to time the release of active mesalamine to the areas affected by colitis. The most common mesalamine release mechanisms include azo-bond prodrug carriers, pH-dependent dissolution, and moisture-sensitive product dispersion. Novel technology has resulted in the development and FDA-approval of a multi-matrix release (MMX) mesalamine. Pharmacodynamic studies suggest a reliable drug delivery system with homogenous release throughout the entire colon. By incorporating the largest amount of mesalamine (1.2 g) per pill, this new product dramatically decreases the number of pills needed to attain a therapeutic daily dosage, and is the first agent approved at once-daily dosing. These factors are expected to increase patient compliance with prescribed mesalamine dosing, and in turn decrease relapse rates of active ulcerative colitis.