Numerous metal allergies possibly resulting from intraoral metal restorations have been reported, although the mechanism of onset is not yet completely understood. Allergen elimination may be the most effective treatment, and location of allergen metal becomes essential. The x-ray flourescence spectroscope was used to detect the allergen metals in intraoral metal restorations and personal and household items of metal allergy patients. The apparatus was evaluated preceding its clinical application, and restorations and personal items for 381 pateints were analyzed to detect allergens. Successful diagnoses and allergen elimination treatment of three patients are reported.