Patients presenting to a chest clinic because of adult-onset wheezing with no history of allergy had a 90 percent prevalence of gastroesophageal reflux, even though reflux symptoms were mild or absent. Ninety patients were randomly assigned to receive cimetidine or an identical placebo or to undergo antireflux surgery. During a six-month period, all groups improved clinically; the cimetidine and surgical groups improved more than the placebo group. The intake of pulmonary medication decreased significantly in both cimetidine and surgical groups. Pulmonary function test results improved in the cimetidine- and surgically treated patients; improvement was not statistically significant. At long-term follow-up, the surgical group maintained clinical improvement and decreased pulmonary medication intake, whereas the placebo group worsened. We conclude that gastroesophageal reflux can play a significant role in some patients with nonallergic pulmonary disease and that its treatment can improve pulmonary symptoms and objective measurements of pulmonary function.