This study was conducted on 39 patients whose severe attacks of bronchial asthma with disturbance of consciousness required admission to the ICU of our hospital between 1984 and 1989. Among the 39 patients, there were 16 deaths. Most patients collapsed suddenly at home and were taken to our hospital. Arterial blood gas analysis at the time of admission to the ICU revealed that the PaO2 levels were as high as 252.6 +/- 57.6 (mean +/- S.E.) Torr in non-survivors and 221.0 +/- 29.7 Torr in survivors, with no significant difference because of prior oxygen therapy in almost all cases. Systolic blood pressure was 14.8 +/- 10.8 (mean +/- S.E.) mmHg, with marked circulatory disturbance in the fatal cases. Most patients displayed marked disturbance of consciousness, but maintenance of blood pressure led to recovery without sequelae despite marked disturbance of consciousness in most patients.