This study evaluated pharmacokinetics of 5-ASA and N-Ac-5-ASA associated with each of 3 regimens of oral mesalamine 2.4 g/day (Lialda 2.4 g/day 2 x 1.2 g every 24 hours, Asacol® 6 x 400 mg every 24 hours, or Asacol 2 x 400 mg every 8 hours). Primary endpoints were 5-ASA area under the plasma concentration versus time curve from zero to 24 hours (AUC24) and total 5-ASA percent of dose excreted (A'e [%]) over the 24-hour period on Day 7.