Bronchopulmonary lavage (BAL) has provided a fresh dimension for the investigation of pulmonary and multisystem disorders. BAL fluid may be analysed for cells and chemical mediators in the diagnosis and also serially for the management of several granulomatous disorders including sarcoidosis, extrinsic allergic alveolitis, chronic beryllium disease, talc granulomatosis, tuberculosis, Langerhans' histiocytosis-x and Crohn's disease. It may also provide information in fibrosing alveolitis, collagen vascular disease, occupational and drug-induced lung disease, acquired immune deficiency syndrome, bronchial asthma, neoplasia, transplantation, pulmonary alveolar proteinosis and eosinophilic lung disease. This survey analyses the value of BAL and how it has provided a new window for the chest physician.