Résumé : After a short historical review a proposal is made for the definition of nasal polyposis. The authors studied 350 CT-scans of patients with nasal complaints. In a high percentage anatomical anomalies were observed. In 57.5% of the CT-scans sinus mucosal disease was visible. In all patients with maxillary sinus disease polyps (rounded structures) could be found; in 31% these polyps were mainly of grade 2. From a retrospective study of 111 biopsies of nasal polyposis (65 patients) it became clear that different polyps from the same patient showed substantial difference in cellular content, i.e. presence of eosinophils, neutrophils, plasma cells, glands, ducti and thickening of the basal membrane. As oral acetylsalicylic acid provocation may be hazardous in ASA-sensitive patients, the authors developed a nasal aspirine provocation test. This nasal ASA test was carried out in 10 normal subjects, 10 patients with aspecific hyperreactivity, 10 atopic patients and 16 patients with polyposis nasi. The reproducibility of the test, however, was so poor that the nasal ASA challenge test in its present form does not appear to be of any great clinical value. Finally, the authors discuss the physiopathology of nasal polyposis.