A new device for the administration of bronchodilators to asthmatics by nebulisation has been developed. Nebuliser therapy, in many patients more effective than other forms of drug delivery, has been limited by the need to provide patients with units driven by compressed air. Solutions can be nebulised by contact with a rapidly spinning horizontal disc. Adaptation of this method to a small nebuliser for clinical use is difficult, since a constant delivery of fluid the centre of the disc is necessary. The problem has been overcome in the new device in which the disc spins vertically in a reservoir. The performance of the prototype device was compared with that of a conventional compressed air nebuliser. The improvement is spirometry values of 8 asthmatic patients was similar for both nebulisers.