High-resolution CT allows a more precise assessment of the presence, pattern and distribution of parenchymal and airway abnormalities than a chest radiograph. It has the advantage over lung biopsy of providing an overall view of the extent and pattern of parenchymal involvement rather than being limited to a small region, which may not be representative of the overall pattern of disease. However, there is limited information on the correlation between the findings on HRCT and histological patterns in drug-associated lung disease. Data based on a small number of cases suggest that the different histological patterns of drug reaction are not reflected by distinctive HRCT findings (Cleverley et al, 2002) . *Correspondence: Professor NL Müller; E-mail: nmuller@vanhosp.bc.ca Despite these limitations, it seems reasonable to approach the radiological manifestations of drug-associated lung disease by the use of the underlying histological pattern (Ellis et al, 2000; Myers et al, 2003) . Using such an approach, the most common manifestations can be classified into diffuse alveolar damage, hypersensitivity pneumonitis, organising pneumonia, nonspecific interstitial pneumonia (NSIP) and eosinophilic pneumonia (other less common drug reactions are not discussed here). Any one histological pattern can be caused by a number of different drugs. Furthermore, similar histology is found in other conditions that are not associated with drug use, such as idiopathic interstitial pneumonias, viral, bacterial and fungal pneumonia, pulmonary haemorrhage or leukaemia and collagen vascular disease. Occasionally, HRCT may demonstrate findings that are highly specific for the diagnosis, including increased attenuation in amiodarone lung and areas of fat attenuation in lipoid pneumonia.