The success of inhalation therapy depends on patients inhalation technique and correct handling of the inhalation device. In this study the effort to train correct handling and optimal inhalation technique of patients using Autohaler and Turbuhaler was assessed. The Bad-Reichenhall-Aerosol-Therapy-Trial (BREATH) was a prospective, randomized, cross-over trial in 200 patients who were not familiar with either of the test systems. The correct handling of Autohaler and Turbuhaler was assessed by means of a checklist (observation score). An optimal inhalation maneuver was used evaluated with the computer-based Inhalation Manager (optical feedback, computer score). The Autohaler reached 6.58 +/- 3.64 (mean +/- SD) out of nine points in the observation score and 66.85 +/- 29.84% in the computer score before training. After training the scores increased significantly to 8.33 +/- 2.08 points and 86 +/- 23.40% respectively. The use of the Turbuhaler also significantly improved from 4.28 +/- 4.24 points and 56.67 +/- 42.97% to 7.78 +/- 2.74 points and 85.80 +/- 27.63%, respectively. The significant improvement of patients inhalation technique after training emphasizes the importance of training in inhalation therapy. In addition, it could be demonstrated that the optical feedback given by the Inhalation Manager was a useful tool for improving the inhalation technique of patients using Autohaler and Turbuhaler.