Localised alveolar-septal amyloidosis has been thought irreversible. A woman exposed to the dust of sea-snail shells during the manufacture of nacre buttons had clinical and immunological features typical of hypersensitivity pneumonitis; however, transbronchial lung biopsy showed alveolar-septal amyloidosis. There was no evidence of other diseases known to be associated with amyloidosis, nor were amyloid deposits found in other organs. After a year without exposure to the antigen there was no trace of either pneumonitis or amyloidosis.