Food allergy is a common health problem worldwide, with increasing prevalence during recent decades. The only approved treatments for food allergy are food avoidance and administration of emergency medications in case of accidental exposure, which negatively affects patients' quality of life, so new treatments are highly desirable. Different food immunotherapy modalities have recently been used, with variable success rates in the induction of desensitization and tolerance, and different numbers and types of adverse reactions. Adverse reactions, especially intolerable gastrointestinal symptoms, are the most important causes of immunotherapy withdrawal. Eosinophilic esophagitis has been reported as a complication of milk, egg, and peanut oral immunotherapies and sublingual immunotherapy for respiratory allergies, but not for food allergies. Eosinophilic gastritis and eosinophilic colitis also rarely happened following egg and milk oral immunotherapies. The patients undergoing oral and sublingual immunotherapies should be closely followed up for a long time, and those with gastrointestinal symptoms should be evaluated by endoscopy of the gastrointestinal tract. These complications are usually reversible after early diagnosis and stopping the immunotherapy protocol.