Arformoterol is an N-[2-hydroxy-5-(1-hydroxy-2-{[1-(4-methoxyphenyl)propan-2-yl]amino}ethyl)phenyl]formamide in which both of the stereocentres have R configuration. The active enantiomer of formoterol, it is administered by inhalation (generally as the tartrate salt) as a direct-acting sympathomimetic and bronchodilator for the treatment of chronic obstructive pulmonary disease (any progressive respiratory disease that makes it harder to breathe over time, such as chronic bronchitis and emphysema). It has a role as a bronchodilator agent, an anti-asthmatic drug and a beta-adrenergic agonist. It is a conjugate base of an arformoterol(1+). It is an enantiomer of a (S,S)-formoterol.