Asthma and chronic obstructive pulmonary disease (COPD) are characterized by airway obstruction, hyperresponsiveness and inflammation. The tachykinins substance P and neurokinin A are present in the human airways where they are found in sensory nerves and immune cells. Tachykinins are released in the airways after inhalation of ozone, cigarette smoke or allergen. They interact in the airways with tachykinin NK1, NK2 and NK3 receptors to cause bronchoconstriction, plasma protein extravasation, and mucus secretion and to attract and activate immune cells. In preclinical studies they have been implicated in the pathophysiology of asthma and COPD, including allergen-and cigarette smoke-induced airway inflammation and bronchial hyperresponsiveness. So, tachykinin receptor antagonists have potential in the treatment of asthma and COPD. With the arrival of more potent dual and triple tachykinin receptor antagonists the tools to obtain a more definite judgment about the role of tachykinins in airway diseases such as asthma and COPD are now available.