Recent studies have suggested that allergic fungal rhino-sinusitis could be involved in the development of nasal polyposis. The aim of this study was to evaluate the response of anti-fungal nasal lavages. Patients performed nasal lavage with 20 ml of a one per one thousand amphotericin B suspension in each nostril, twice a day, for four weeks. In addition, all patients continued their saline nasal lavage and their conventional topical corticosteroid spray. This study included 74 patients, with a mean age of 46 years (range from 19 to 73). Before anti-fungal treatment, the distribution of nasal polyposis, according to Malm, was: 13 patients in stage I (17.5 per cent), 48 patients in stage II (65 per cent) and 13 patients in stage III (17.5 per cent). After anti-fungal nasal lavages, the total disappearance of nasal polyposis was observed in 29 patients (39 per cent). Eight patients were stage I, 21 stage II, and none stage III. In patients who have had previous endoscopic polypectomy and functional endoscopic sinus surgery, total disappearance of nasal polyposis was seen in 24 patients (47 per cent). Hyper-reactivity to fungal organisms could be one of the mechanisms underlying the development of nasal polyposis. A direct effect of amphotericin B suspension on the integrity of the cell membrane of the polyps’ epithelium could not be excluded.