Abstract: A pharmaceutical aerosol formulation comprising particles of formoterol or a pharmaceutically acceptable salt, solvate or physiologically functional derivative thereof, said particles being suspended in the formulation; a compound of the formula (I), in which: R1 is 1-butyl, 2-butyl, cyclohexyl or phenyl and R2 is acetyl or isobutanoyl, said compound of formula (I) being dissolved in the formulation; and a propellant selected from 1,1,1,2-tetrafluoroethane, 1,1,1,2,3,3,3-heptafluoropropane and a mixture thereof.