Nebulization treatment of acute asthma with terbutaline and ipratropium bromide, given either separately with a 30-minute interval or combined as single inhalation, was compared with injection treatment with a combination of terbutaline given subcutaneously and theophylline given intravenously. Seventy-seven episodes of acute asthma were studied. Nebulization treatment gave the same degree of bronchodilation as the injections, both immediately after treatment [measured as increase in forced expiratory volume in 1 second (FEV1) in peak expiratory flow rate (PEFR) and improvement of dyspnoea] and during the following 6 days (measured by PEFR recordings at home). The injection treatment caused a moderate increase in heart rate, whereas no circulatory side-effects were noted during nebulization treatment. Administration of ipratropium bromide 30 minutes after terbutaline was not more effective than the combination of both substances as a single nebulization.