Food allergy occurs in 1.5% to 6% of the population. However, confirming the diagnosis of food allergic disorders is often difficult because of the lack of reliable, convenient testing and our incomplete understanding of the underlying pathophysiology. Several recent studies have expanded the knowledge regarding the pathophysiology and diagnosis of food allergy. Rodent models have elucidated several mechanisms of mast cell-mediated responses and antigen transport. Although it had been suggested that certain allergic disorders have a genetic predisposition, investigators are now identifying genomic mutations associated with specific atopic conditions in humans. A novel endoscopic method may provide insight into diagnosis, as well as pathophysiology of allergic disorders.