The non-selective muscarinic antagonist ipratropium is widely used as bronchodilator. Due to its pharmacokinetic properties this drug, after inhalation, acts only locally on the airways and no unwanted anticholinergic side-effects are observed. Another approach is the use of selective muscarinic antagonists. Based on their selectivity for M3- and/or M1-receptors such drugs might show bronchospasmolytic properties without the occurrence of typical atropine-like side effects even after systemic administration. Pharmacological data of the in vivo bronchoselectivity of pirenzepine (M1-selective) and AQ-RA 721 (high affinity for M1- and M3-receptors) is presented and the use of these drugs as bronchodilators is discussed.