To date, most RCTs have been conducted among adult patients and efficacy in children has been extrapolated from these data. However, childhood inflammatory bowel disease (IBD) may not be similar to adult onset disease. The prevalence of extensive colitis proximal to the splenic flexure is doubled in pediatric-onset UC compared to adults and extensive disease is consistently associated with more severe phenotype. On the other hand, studies in children with IBD often show better response to therapy than in adults. Therefore, American and European regulating agencies encourage pediatric studies be conducted for all approved drug products. It has been found that less than 50% of children with IBD are adherent with treatment, a figure associated with the understanding of the disease which is generally lower than in adults. Therefore, the advantage of once daily dosing of 5-ASA over twice-daily may be greater in children compares with adults.