The lectins wheat germ agglutinin (WGA) and Concanavalin A (ConA) were perfused into an isolated small intestinal segment alone or after prior perfusion with neuraminidase for a 10 day period in the rat. Intestinal morphometry, intraepithelial Lymphocyte (IEL) and round cell content as well as digestive capacity was measured in the loop and in the adjacent segments. Both lectins induce a mucosal transformation in all segments but ConA is more effective than WGA. Pre-incubation with neuraminidase enhances the action of ConA throughout, whereas only a partial enhancement of the effect of WGA is observed. The mucosal transformation after long term perfusion with the lectins resembles the hyperregenerative adaptation of the mucosa due to gluten in coeliac disease and may thus serve as an animal model for this disease.