A combination which comprises (a) a PDE4 inhibitor and (b) an antagonist of M3 muscarinic receptors which is (3R)-1-phenethyl-3-(9H-xanthene-9carbonyloxy)-1-azoniabicyclo[2.2.2]octan- e, in the form of a salt having an anion X, which is a pharmaceutically acceptable anion of a mono or polyvalent acid.