The lung is highly amenable to topical therapy in the form of inhaled drug preparations and this route is utilised in the treatment of the majority of respiratory disease. The inhaled route offers a number of important potential advantages for administration of therapy to patients with IPF. Firstly, by limiting systemic exposure to drugs, the inhaled route offers the potential for achieving higher lung doses of drugs that might otherwise cause systemic toxicity. Secondly, inhaled treatment may more effectively reach the areas of abnormality in IPF, namely the hyperplastic epithelium and the underlying fibroblastic foci. Thirdly, the inhaled route offers an alternative to parenteral administration of compounds that are poorly absorbed through the gastro-intestinal tract e.g. monoclonal antibodies. It should be noted however, that the fibrosis in IPF develops peripherally involving the alveolar interstitium and the terminal bronchioles. Furthermore, the disease causes architectural destruction and distortion of the lung that is liable to alter the normal laminar flow of air (and inhaled particles) through the bronchial tree. It is therefore, by no means certain that it is possible to deliver inhaled therapies directly to regions of fibrosis in IPF.