A reticular pattern on high resolution CT (HRCT) invariably represents significant lung pathology and is the dominant feature of irreversible fibrosis. We present two cases of nitrofurantoin-induced pulmonary toxicity in which the initial HRCT showed a widespread reticular pattern and associated distortion of the lung parenchyma, thought to represent established fibrosis. Follow-up HRCT scans after withdrawal of the drug showed resolution of this supposedly irreversible pattern.