Proteases present in our Gastro-Intestinal (GI) tract enable us to digest the proteins in our food. Normally proteases are neutralized along their transit through the GI tract. However, in babies and infants the GI tract is not yet fully functional. This means that the proteases are not completely neutralized during the transit through the GI tract and are still active upon excretion. Active proteases possess proteolytic (the breakdown of proteins) activity that damages the sensitive perianal skin.