Changes in pulmonary resistance induced by various nasal stimuli were recorded in 16 subjects with nasal allergy and 16 laryngectomized subjects. To avoid human errors in sampling respiratory curves, computer analysis was performed breath by breath, automatically and continuously. In the subjects with nasal allergy the nasal mucosa was stimulated with pressure using a nasal balloon, and by a paper patch with 0.1 ml of 5% histamine hydrochloride. Laryngectomized subjects were stimulated with pressure and by pepper powder. Nasal pressure stimulation up to 50 cm H2O did not cause a statistically significant change in the pulmonary resistance of both groups of subjects. Pepper stimulation caused a statistically significant increase of the pulmonary resistance amounting to 40.4 +/- 28.2% of the prestimulatory level. Histamine stimulation caused a statistically significant change of the pulmonary resistance, but it was difficult to discern whether it caused an increase or a decrease of the resistance. Maximum efforts were used to control the respiratory pattern using the metronome and by visual monitoring of the peak flow rate on the cathode ray oscilloscope, but pepper and histamine stimulation caused a statistically significant increase, although slight, of tidal volume. The effect of slight changes of respiratory patterns induced by nasorespiratory reflex on the observed change of pulmonary resistance could not be ruled out in this human study.