Summary In pulmonary congestion dyspnoea is due not only to an increase in elastic but also in viscous work. Increased airway resistance can be reduced in most of these cases by inhalation of adrenergic or anti-cholinergic agents. Therefore, besides bronchial mucosal swelling induced by congestion in the bronchial vessels via bronchopulmonary anastomoses, bronchospasm can take place and lead to cardiac asthma. The possible genesis of this bronchoconstriction is discussed.