Asacol is a delayed-release tablet formulation designed to deliver mesalamine (also known as mesalazine) at a pH ≥ 7.0. This property results in release of the drug in the terminal ileum and beyond. Physiologic factors such as the pH of the surrounding medium, transit times in the intestinal regions of interest, and the rate and extent of absorption and metabolism govern Asacol drug release and delivery, which in turn influence the pharmacokinetic profile of the delivered drug. These physiologic factors and their effect on Asacol pharmacokinetics have been studied in adults, but corresponding studies in children have not been performed. However, relevant studies describing the gastrointestinal pH; transit times; and pharmacokinetic aspects of drug absorption, metabolism, and excretion in pediatric patients (relative to adults) provide reasons to expect that the performance characteristics of Asacol in the pediatric population will be similar to those measured in adults.