A device is disclosed for the preparation of nebulised droplets, for inhalation. The device has: a surface acoustic wave (SAW) transmission surface； a SAW transducer adapted to generate and propagate SAWs along the SAW transmission surface； and an array of cavities opening at the SAW transmission surface for containing a liquid. In operation, SAWs propagating along the SAW transmission surface interact with the liquid in the cavities to produce nebulised droplets of the liquid. Operation of the device results in a nebulised plume of droplets of average diameter in the range 1-5 μm.
