The diagnosis of idiopathic pulmonary fibrosis can be made only after exclusion of other entities such as neoplasm, toxic treatments, collagen vascular diseases, occupational exposure or granulomatous diseases, such as sarcoidosis. The repercussions on gas exchanges are the most reliable indications of the severity of the disease, the measure of lung volume or chest x-rays alone often being misleading. Biopsies obtained during transbronchial procedures by thoracoscopies or thoracotomy are of great help, but mainly to rule out other diseases. In many cases, only a high resolution computerised tomography (CT) scan and bronchoalveolar lavage are performed to rule out infection or tumour and to assess the inflammatory state of the disease. Due to the fact that barely a quarter of patients respond to corticosteroids alone, cytostatics (in particular azathioprine) are often prescribed simultaneously with low dose corticosteroids, either initially or after an unsuccessful trial of corticosteroids. Cyclosporin has been useful for only a limited number of patients. Colchicine has been shown useful in an open trial but its role still needs to be assessed. Anticytokine therapy and the role of substances such as relaxin are still at the experimental stage. Lung transplantation is now a therapeutic option for selected patients.