Food protein–induced enterocolitis syndrome (FPIES) was first described in detail in the late 20th century as a non–IgE-mediated food allergy characterized by delayed gastrointestinal symptoms after ingestion of a trigger food. Although the initial case series reported infants reacting to cow’s milk– and soy-based formulas, we now recognize that FPIES affects patients across the age spectrum. This brief review highlights our evolving understanding of FPIES with a discussion of triggers, epidemiology, food challenges, and pathophysiology. Food protein–induced enterocolitis syndrome (FPIES) was first described in detail in the late 20th century as a non–IgE-mediated food allergy characterized by delayed gastrointestinal symptoms after ingestion of a trigger food. Although the initial case series reported infants reacting to cow’s milk– and soy-based formulas, we now recognize that FPIES affects patients across the age spectrum. This brief review highlights our evolving understanding of FPIES with a discussion of triggers, epidemiology, food challenges, and pathophysiology.