Diffuse alveolar haemorrhage associated with glomerulonephritis is a rare but serious complication of d-penicillamine therapy. A case is reported which illustrates the usefulness of bronchoalveolar lavage and kidney needle biopsy for the early diagnosis of this condition. A search for antiglomerular basement membrane antibodies in serum was negative, whereas antigranulocyte cytoplasmic antibodies were present. These immunological results differentiated the disease from Goodpasture's syndrome to which it is clinically related and placed it in the same category as microscopic polyarteritis. After treatment with corticosteroids, cytostatic drugs and plasmapheresis, the outcome was favourable in contrast with the usually poor prognosis.