Two treatment regimens for the initial treatment of acute wheezing were evaluated in 61 wheezing infants. Thirty-one patients received fenoterol (F) (0.1 mg/kg) and placebo (P) and 30 patients received fenoterol (F) (0.1 mg/kg) plus a fixed dose of ipratropium bromide (IB) (50 micrograms). Both groups received the drugs by inhalation using an ultrasonic nebulizer and face mask. A clinical score system based on wheezing and rib cage retraction was established and evaluations were performed before and at 15, 30, and 45 minutes after treatment. After the last evaluation based on the clinical score, it was decided whether to repeat or not to repeat the treatment. Our results showed that a combination of a beta agonist and ipratropium bromide (FB) was more effective than a beta agonist alone (F) in reducing wheezing and dyspnea during an acute attack (63.4 versus 25.8%; p less than 0.05).