&NA;Nematode parasites of the gastrointestinal tract occupy different niches on or within the mucosa. The epithelial and mucosal changes have many features that are characteristic of allergic inflammation, including altered epithelial secretion, recruitment of eosinophils, basophils, and mast cells, and production of immunoglobulin E. The role of T‐cell subsets in the induction of these changes is the main focus of this review.Current Opinion in Gastroenterology 1993,9:986‐993