(August 2003) The mucous membranes are one of the largest organs of the body (Figure 1). Collectively, they cover a surface area of more than 400m2 (equivalent to one and a half tennis courts) and comprise the linings of the gastrointestinal, urogenital and respiratory tracts [15,18]. Figure 1: Schematic diagram of the mucous membranes of the body and surfaces with which they are in contact. These mucosal surfaces, while located inside the body, are actually a physical barrier between the outside and the sterile interior cavity of the body known as the “systemic” environment. Critical nutrients, oxygen and other molecules…