Enteral nutrition has a positive effect on growth in children with active Crohn's disease. The question arises: is this is due only to improved nutrition? Enteral formulas may also directly reduce inflammation, lowering the expression of cytokines like interleukin (IL)-6 that inhibit growth. Four lines of evidence support the hypothesis that enteral formulas directly lessen inflammation: enteral nutrition directly affects the inflamed intestine; changes in inflammatory markers precede repletion of nutrition status; molecular pathways exist linking changes in luminal contents to the expression of class II MHC genes in intestinal epithelium in animal studies; and enteral formulas have a direct effect on cytokine expression by intestinal epithelial cells.