Abstract The gingival sulcus wall of Dutch Belted rabbits was used to study vascular transudation and exudation with Pelikan ink as a tracer for light microscopy and saccharated iron oxide as an electron microscopic tracer. The marker was apparently transported by numerous plasmalemmal vesicles, and also passed through the interendothelial junctions. The sulcular fluid was an inflammatory exudate rather than a transudate. Ultrastructural alterations of the gingiva following inflammation were studied. The interepithelial space increased more on the sulcular than the attached gingival side. The wider interepithelial space in the sulcular area and the non-keratinizing nature of this tissue may have contributed to the ease of passage of the gingival fluid in that region.