Adverse food reactions (AFR) are a common problem that may cause cutaneous and / or gastrointestinal signs in dogs and cats. They comprise food intolerance, food intoxication, and food allergy. Response to a dietary elimination trial and recurrence of signs during dietary provocation remain the centerpiece of diagnosis and management of dogs and cats with AFR. Response to an elimination trial is frequently observed in dogs and cats with chronic idiopathic enteropathies. However, only a fraction of them relapse after a dietary challenge. These animals may have mild to enteritis and/or colitis and benefit from various additional properties of the elimination diet.