The tussive and bronchoconstrictive effects of hyperpnea with cold air (HCA) are described in 3 patients with exercise-induced cough, 7 volunteers with exercise-induced cough, and 7 asymptomatic volunteers. Cough associated with HCA exceeded baseline cough in each of the patients and volunteers with exercise-induced cough and in all but one of the asymptomatic volunteers. The time course of cough was similar in each group. Maximal cough frequency occurred during the first 5 min after HCA and persisted to a much lesser degree during the ensuing 26 min. The time course of bronchoconstriction was similar to that of cough, with maximal decrements in specific airway conductance measured 5 min after HCA. Pretreatment with albuterol blocked HCA-induced bronchoconstriction but had no effect on HCA-induced cough. No subject in any of the 3 groups was hyperreactive to methacholine aerosols. In subjects who are nonhyperreactive to methacholine aerosols, HCA has a characteristic, reproducible, and predictable tussive effect. Thus, HCA may be a useful tool for investigating the mechanism of cough and for evaluation of antitussive drugs.