The intestinal epithelium continues to be an excellent model system for studying regulation of gene expression during lineage commitment and differentiation. Recent studies have provided new insights into intestinal growth and adaptation and intestine-specific gene expression. The role of previously characterized growth factors, such as transforming growth factor-α, transforming growth factor-β, or growth hormone, has been investigated in the intestine. In addition, members of a newly described gene family called the trefoil peptides are being studied in the intestine and new insights into their functional significance are emerging.