Many patients benefit from using metered-dose inhalers (MDIs) with spacer or reservoir devices. Concomitant therapy with separate MDI doses of cromolyn sodium and a beta-agonist is common practice. If two puffs from each drug could be placed into a chamber, the patient could administer both medications at once, enhancing compliance. A multistage liquid impinger (a four-stage inertial impaction device incorporating an inlet bend and an absolute filter, which separates an aerosol cloud into six fractions) was used to investigate such a possibility. Cromolyn sodium and albuterol MDIs were used with an Aerochamber (Monaghan Medical Corp., Plattsburgh, N.Y.) and an Inspirease (Schering Corp., Kenilworth, N.J.). Results are reported by analyzing milligrams of cromolyn sodium per actuation retrieved. With the Aerochamber, two puffs of cromolyn sodium followed by two puffs of albuterol resulted in the total "dose to patient" being reduced by 75% (0.19 versus 0.05 mg) and the effective dose of fine particles (less than 6.5 microns) being reduced by 80% (0.13 versus 0.03 mg) compared to two puffs of cromolyn sodium alone. With the Inspirease, total dose was decreased by 80% (0.32 versus 0.06 mg), whereas the effective dose of fine particles was reduced by 60% (0.19 versus 0.05 mg) compared to one puff of cromolyn sodium alone. The use of cromolyn sodium and albuterol MDIs in a multipuff combination with the Aerochamber or the Inspirease is not recommended because this leads to a loss of the dose delivered compared to a single administration.