- Background: Paediatric Ulcerative Colitis (UC) is more extensive than adult disease, and more often refractory to mesalamine. However, no prospective trials have evaluated mesalamine enemas for inducing remission in children. Our goal was to evaluate the ability of mesalamine enemas to induce remission in mild to moderate paediatric UC refractory to oral mesalamine. Methods: This was an open label arm of a previously reported randomized controlled trial of once daily mesalamine in active paediatric UC (MUPPIT trial). Children, aged 4-18 years of age, with a PUCAI score of 10-55 were enrolled after failing at least 3 weeks of full dose oral mesalamine. Patients treated with steroids or enemas in the previous month and those with isolated proctitis were excluded. Children received Pentasa enemas 25 mg/kg (up-to 1gr) daily for three weeks with the previous oral dose. The primary endpoint was clinical remission by week 3. Results: Thirty eight children were enrolled (mean age 14.6?2.3 years; 17/38 (45%) with extensive colitis). Clinical remission was obtained in 16 (42%) while response was obtained in 27 (71%) at week 3. Eight children deteriorated and required steroids. There were no differences in baseline parameters between those who entered or failed to enter remission, including disease extent (43% in left sided and 41% in extensive colitis) and disease activity (44% in mild and 41% in moderate activity). Conclusion: Clinical remission can be markedly increased in children who are refractory to oral mesalamaine by adding mesalamine enemas for 3 weeks, prior to commencing steroids.