Because of their biological affinity for normal gastrointestinal (GI) mucosa, eosinophilic granulocytes are "normal residents" in the mucosa. This physiological GI eosinophilia translates into a state of "permanent normal inflammation", which means that the mucosa's local immune system is constantly confronted by dietary proteins and indigenous microorganisms. This eosinophilic infiltration of the GI mucosa is increased, reactively, in the course of local inflammatory processes, collagenosis, infections (especially helminthic infections), vasculitis, neoplasms and IgE-dependent allergic reactions to food. Lastly, GI eosinophilia that is clearly aggressive, both because of its intensity and its persistence, is what characterizes eosinophilic gastroenteritis. In the present article, we summarize the ethiopathogenic and clinico-epidemiological features of this process, as well as its position within the field of immunopathologic food intolerance.