One hundred and ninety-nine elderly men and women were assessed for their pulmonary function and their mental ability. One hundred and twenty-one patients had a PEFR less than 70% of the predicted for their age and height. Reversibility tests showed that 82 patients had 15% or more improvement in their PEFR following 200 micrograms salbutamol. However, only 6% of the patients were receiving respiratory-related medication. Further analysis showed that there was no correlation between the patients' age, sex, amounts of sputum production, wheeze, breathlessness, smoking habits, chest expansion, hospitalization, mental function and airway reversibility. 'Reversible' patients did, however, have a high incidence of cough and a low pre-test PEFR value. The predominant symptom of 'reversible' and 'non-reversible' patients was cough. The study emphasizes the importance of routinely performing lung function tests in elderly patients and the use of reversibility tests to identify reversible airways obstruction. These results suggest that in old age potentially reversible airways obstruction is often overlooked or misdiagnosed.