This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The investigators hypothesize that low dose naltrexone therapy will be effective in the treatment of pediatric patients with Crohn's disease. In order to examine this hypothesis, they propose to investigate the effects of low dose naltrexone on a cohort of thirty patients with active Crohn's disease in a randomized double-blind placebo controlled cross-over trial.