Background: Primary intestinal lymphangiectasia (PIL) is a rare digestive disease and most articles on this condition are isolated case reports. Aims: Our purpose is to investigate the clinical characteristics, therapeutic management, and outcome of PIL through case studies. Methods: We conducted a retrospective analysis and obtained detailed clinical information for four PIL patients treated at our institution. A MEDLINE database search was also performed using the search term "intestinal lymphangiectasia" and all pertinent literature was carefully reviewed. Results: Four children treated in our department showed elevated IgE and a good response to diet intervention. After reviewing the literature, we conducted statistical analysis on the basis of all the cases, with a total of 84 cases. Thirty-eight cases have been reported with diet treatment, 24 (63%) of whom showed apparent improvement in clinical symptoms and laboratory parameters. Four cases (5%) had a malignant transformation of lymphoma, and the average time from PIL onset to lymphoma diagnosis was 31 years (range, 19-45 years). No difference was observed regarding the presence of major clinical manifestations among children and adults. Diet intervention in children was more effective than that in adults. Conclusions: Diet intervention is the cornerstone of PIL medical management, which was found to be more effective in children than in adults. Early diagnosis and treatment of IL is of great importance for effective diet therapy. An elevated IgE level should be monitored periodically since it could be an indication of malignant transformation-lymphoma. © 2010 Springer Science+Business Media, LLC.