Young lifetime nonsmoking patients (9) with symptoms of rhinitis but without any history of asthma or wheezing and 9 age-matched healthy lifetime nonsmoking control subjects were studied with respect to subdivisions of lung volume, forced vital capacity, forced expiratory volume (1.0 s), and flow-volume curves breathing air, and also breathing a mixture of 80% h-20% O2 from which were obtained airflows at 50% VC [vital capacity] (.ovrhdot.Vmax50), the percentage increase in .ovrhdot.Vmax50 breathing He-O2 as compared to air (.DELTA..ovrhdot.Vmax50) and the point where He-O2 and airflow-volume curves became identical (Viso.ovrhdot.v) [iso-flow volume]. No significant differences between the 2 groups in age, subdivisions of lung volume or forced expiratory airflow rates were recorded. .DELTA..ovrhdot.Vmax50 was significantly lower in the patients (16.4 .+-. 12.0) compared to the controls (47.7 .+-. 16.4) (P < .001) and Viso.ovrhdot.v was higher in the patients (28.4 .+-. 14.9) as compared to the controls (14.4 .+-. 7.6) (P < .01). After bronchodilator therapy .ovrhdot.Vmax50 increased the control subjects (P < .005) but not in the patients and .DELTA..ovrhdot.Vmax50 decreased in the control group but was unchanged in the rhinitis patients. Patients with rhinitis who have normal airflow rates possibly may have peripheral airways obstruction not readily reversible with bronchodilators.