Inhalation of aerosolized aminophylline solution (Neophylline) was examined for it's bronchodilating effect. Tests were done on the patient with bronchial asthma aged from 8 to 16 years of age which were divided into two groups, i.e., 21 wheezy patients, 8 non-wheezy patients and on another 14 under normal controls. 1.2 ml. of neophylline (30 mgs. of aminophylline) was inhaled to each patient by the micronebulizer for 6 minutes. VC, FEV1, PFR, V50 and V25 were measured by a Flow-volume recorder OST 7OD just before and after inhalation. The results showed that the bronchodilating effect of inhaled neophylline was detected in the wheezy patients group but not in the non-wheezy patients group nor in the control group. Furthermore, the duration of the bronchodilating effect was examined on another 19 wheezy patients by a peak flow meter. The effect appeared to be sustained for 4 hours after inhalation. Inhalation of serosolized neophylline is considered to be useful because of the fact that the bronchodilation can be obtained without an elevation of serum concentration of theophylline.