This is a retrospective review of 74 consecutive patients who presented with a nasal septal perforation or ulcer. The aim of this study was to evaluate the contribution of the investigations used to identify the pathology underlying their septal perforation or ulcer. In the majority of cases there was an anterior (85 per cent) smooth, well-circumscribed septal lesion with an occasional bleeding point. Seventy-seven per cent were less than two cm in diameter. The primary presenting symptom was intermittent epistaxis, with the exception of patients with granulomatous disease, who presented more frequently with nasal obstruction. Thirty-five patients (47 per cent) were idiopathic, 29 (39 per cent) traumatic, eight (11 per cent) inflammatory and two (three per cent) infectious. The nasal septum was biopsied in 71 cases, and histology showed non-specific or non-diagnostic findings in 39 (55 per cent), chronic inflammation in 12 (17 per cent), acute inflammation in six (eight per cent), acute to chronic inflammation in four (six per cent) and histological changes consistent with trauma in nine (13 per cent). The anti-neutrophil cytoplasmic antibody test (ANCA) successfully identified six patients with Wegener's granulomatosis, and the angiotensin converting enzyme test (ACE) supported a clinical diagnosis of sarcoidosis in one patient. The remaining investigation methods (CRP, ESR, chest radiograph, biochemistry and coagulation screen) did not contribute to the diagnosis. In this study, the appearance of a nasal septal perforation or ulcer or its location did not predict the clinical diagnosis. A nasal septal bopsy did not significantly contribute toward the clinical diagnosis. On the basis of these findings, a biopsy of a septal perforation or ulcer is unlikely to contribute to the management of patients unless the supportive tests of ANCA or ACE are abnormal or unless malignancy is suspected. This conclusion is restricted to the management of septal perforations as we have found nasal biopsies of polyps of other lesions to be of value.