Acute asthma can sometimes be severe and potentially life threatening. International guidelines have defined both characteristics of these severe attacks and the associated therapeutic instructions. The efficacy and feasibility of these recommendations were evaluated in 15 asthmatic patients who were admitted to hospital because a severe asthma attack. These patients fulfilled the criteria of severity defined by a British experts conference in the international guidelines published in 1990 in the British Medical Journal. A first line treatment was given to all the patients and included both systemic corticosteroids and inhaled beta 2-agonists. In case of failure, beta 2-agonists were given intravenously and oxygen was administered as required. Monitoring was carried out between the admission and the 8th hour using the following criteria: peak expiratory flow (DP), respiratory frequency (FR), and heart rate (FC). Both DP and FR significantly improved from 196 +/- 79 to 292 +/- 104 l/min (p < 0.01) and from 27.5 +/- 5.5 to 23.7 +/- 5.6 (p < 0.02), respectively. FR remained unchanged (97 +/- 13 vs 98 +/- 13; ns). There was a favourable outcome in all cases. beta 2-agonists administered intravenously were only necessary in two patients for whom no predictive factor could be determined. It is concluded that international guidelines are applicable to severe acute asthma. Inhaled route for beta 2-agonist is sufficient for the majority of patients presenting with the criteria defining severe acute asthma unless life threatening symptoms are present.