Nasal polyposis is a relatively frequent disease of poorly known aetiopathogenesis. In this study the Authors have evaluated the relationship between nasal polyposis and food using elimination diet and the double-blind challenge test. Of twenty-two patients examined, 16 (72.8%) completed the study. Six out of 16 subjects improved when on diet and challenged with specific foods. Two patients were affected by food allergy and 4 by food intolerance. Physical evaluation of nasal polyposis showed an improvement in all 6 patients, while rhinomanometric evaluation showed an improvement in 4 out of 6 patients, after diet. Most patients had an alteration of immunological tests involving IgE or circulating immunocomplexes-mediated mechanism.