A pharmaceutical aerosol is disclosed which is suitable for delivering an active compound to the mucosa of the nose, the osteomeatal complex or a paranasal sinus. The pressure of the aerosol is not constant, but pulsates at a frequency from about 10 to 90 Hz. The aerosol is further characterised in that it exhibits a low effective flow rate of less than about 5 litres per minute. The aerosol is, inter alia, suitable for the prevention, management, or treatment of a disease, symptom, or condition affecting the nose or the paranasal sinuses, such as acute and chronic sinusitis.
