The invention relates to a pharmaceutical composition of unit dose for inhalation by a human subject comprising a topical corticoid and a quinolone or fucidic acid, characterized in that the ratio of the weight of the topical corticoid to the weight of the quinolone or fucidic acid is between 0.02 and 20 and the amount of quinolone or of fucidic acid is less than 1 mg. This composition can be administered by nasal spray and is used for treating the upper and lower respiratory tract, in particular sinusitis and nasal polyps.
