The gastrointestinal (GI) tract provides an intriguing organ for considering the eosinophil's role in health and disease. The normal GI tract, except for the esophagus, is populated by eosinophils that are present throughout the mucosa, raising the possibility that eosinophils participate in innate mechanisms of defense. However, data from clinical studies associates increased numbers of eosinophils with inflammatory GI diseases, prompting concerns that eosinophils may have a deleterious effect on the gut. We present clinical features of 4 disease processes that have been associated with eosinophilia and suggest areas requiring investigation as to their clinical significance and scientific relevance.