The invention relates to products and methods for treating Crohn's disease. The products relate to antibodies that inhibit native human IL-23 while sparing IL-12. One example describes a Phase 1, randomized, double-blind, placebo-controlled, ascending multiple dose study to evaluate the safety, tolerability, pharmacokinctics and pharmacodynamics of an anti-IL-23 antibody (AMG 139) in healthy subjects and subjects with mild to severe Crohn's disease.