A combination which comprises (a) a β2 agonist and (b) an antagonist of M3 muscarinic receptors which is (3R)-1-phenethyl-3-(9H-xanthene-9-carbonyloxy)-1-azoniabicyclo[2.2.2]octane. In the form of a salt having an anion X, which is a pharmaceutically acceptable anion of a mono or polyvalent acid.