Inclusion criteria:  Patients ages 12 months-18 years Presence of clinical symptoms related to esophageal dysfunction such as: feeding aversion, failure to thrive, vomiting, abdominal pain, dysphagia, heartburn, and food impaction Histologic criteria for the diagnosis of EoE with ≥15 eosinophils per high power field from review of a total of six biopsies obtained from the distal and mid (three from each site) esophagus in subjects who were adequately pre-treated with a proton-pump inhibitor- 1mg/kg/dose twice daily, up to a maximum of 40mg or 30mg per dose depending on preparation for 6-8 weeks or had a normal 24 hour ph probe study18 Patients who agree to 4-FED as their treatment of EoE  Exclusion criteria:  Those patients who are on oral or swallowed steroids (prior use of steroids that was discontinued more than two months prior to enrollment does not constitute an exclusion criterion) Patients who are unable to tolerate the 4-FED Patients with concurrent eosinophilic gastroenteritis or eosinophilic colitis