Spacer devices for pressurized metered-dose inhalers (pMDI) are needed to slow down the aerosol jet and hence to reduce oropharyngeal deposition as well as to overcome coordination problems. A new spacer, JET (Chiesi, Italy), which is less cumbersome to carry, was tested on five healthy volunteers. They inhaled with a slow inspiratory vital capacity maneuver 2 x 100 micrograms doses of the beta 2-agonist salbutamol, labelled with 99mTc, via a pMDI (Butovent, Chiesi) with and without the new JET spacer. The percentage of total delivered activity to the lungs increased with the JET from 14.3 +/- 4.5% to 22.3 +/- 4.1%, while the extrapulmonary deposition (oropharynx and stomach) was reduced from 39.8 +/- 12.2% to 11.0 +/- 3.4%. These results show that the optimal application of the JET can improve therapeutic efficacy by reducing extrapulmonary drug deposition while increasing the drug delivery to the lungs. Use of holding chambers as reservoirs should be avoided as well as frequent cleaning of the spacer.