Food intolerance is the term used to describe a hypersensitivity reaction to a food component. These reactions refer to the drug-like side effects caused by a range of chemicals that may be present in food as natural or added components. The range of symptoms which can be induced by food intolerance are very similar to those caused by food allergy, oral allergy syndrome, acute infectious diseases and vesiculobullous disorders; so that on initial presentation, it can be difficult to differentiate between these conditions. A 48-year-old woman with complaints of allergic symptoms was examined with skin prick test (SPT), specific IgE analysis, and oral challenge test for definitive allergen determination. The patient was negative in both specific IgE detection and SPT with commercial extracts of apple, whereas the oral challenge test revealed positive objective symptoms with blister and ulcer formation. Apple has been reported to be the cause of food allergy. To our knowledge, there is no report of apple intolerance in which the lesions are only confined to gingival tissues.