The effect on airway conductance (Gaw) and functional residual capacity (FRC) of stimulation of cold receptors in facial skin was studied in 12 healthy young subjects, with a body plethysmograph. Mean Gaw decreased significantly, from 0.44 to 0.38 liter s−1 cm−1 H2O, in 10 subjects. FRC was only slightly affected, probably because the experiment was too brief to allow air-trapping. It is concluded that the Gaw decrease during exposure to cold results from bronchoconstriction due to (a) stimulation of trigeminal nerve cold receptors and to (b) pharyngeal and glottal airway resistance increase resulting from frequent involuntary 'dry' swallowing.