Intestinal epithelial cells (IECs) are constantly exposed to many commensal microbes and are the primary sites of contact with invading and non-invading enteric pathogens. Galectins are a major type of glycan-binding protein (GBP) that differ from other GBPs by being located mainly intracellularly. These proteins can decode host-derived complex glycans and are involved in various biological responses. Dr. Fu-Tong Liu (Academician, Academia Sinica) is a pioneer and leader in galectin research. Here, we show that galectin-4, a member of the galectin family of animal GBPs, is specifically expressed in gastrointestinal epithelial cells and known to be able to bind microbes to regulate the host innate immune system.