Background: Eosinophilic enteritis, also known as eosinophilic gastroenteritis, is a rare primary eosinophilic gastrointestinal disorder (EGID) of unknown etiology characterized by the presence of an intense eosinophilic infiltrate on histopathology of the intestinal mucosa. Key Messages: The etiology of eosinophilic enteritis remains obscure. There is growing evidence to support the role of aeroallergens and food allergens in the pathogenesis of this disorder as children and adults with EGIDs often have positive skin testing for food allergens and a familial history of allergic diseases. Moreover, significant progress has been made in elucidating that EGIDs involve mechanisms that fall between pure IgE-mediated and delayed Th2 type responses. Preclinical studies have identified a contributory role for the cytokine IL-5 and eotaxin chemokines, providing a rationale for specific disease therapy. Eosinophilic enteritis causes a wide array of gastrointestinal symptoms such as abdominal pain, diarrhea, nausea, vomiting, bloating or ascites, and its diagnosis requires a high degree of clinical likelihood given the nonspecific presentation and physical examination findings. The Klein classification arbitrarily divided patients with eosinophilic enteritis into those with predominantly mucosal, muscle layer or subserosal disease relying on the concept that clinical presentation is dependent on the predominant involved layer of the gastrointestinal tract. Main therapeutic options are represented by oral corticosteroids for a short period with good efficacy. Antihistaminic drugs and sodium cromoglycate have also been used to treat patients with eosinophilic enteritis. Conclusion: Eosinophilic enteritis is generally considered as a benign disease with no relapse, but half of the patients may present a more complex natural history characterized by unpredictable relapses and a chronic course.