Rapid onset of severe and irreversbile airflow obstruction developed in two women. One had eosinophilic fasciitis and the other had rheumatoid arthritis. Both were treated with penicillamine. In the first patient, aged 42 years, dyspnea developed after six months of therapy. Her roentgenogram showed hyperinflation. Forced vital capacity expired in one second (FEV1/FVC%) decreased from 75% to 40%, and the residual volume increased by 1 L. In the second patient, aged 54 years, cough and dyspnea developed after ten months of therapy. The FEV1/FVC% was 56%, the FEV1 was 0.9 L, and the roentgenogram was normal. Lung biopsy specimens demonstrated severe and widespread bronchiolitis. An association between obliterative bronchiolitis and rheumatoid arthritis has been reported. Penicillamine may impair healing of bronchiolitis in such patients.