The way, or ways, in which asthmatics recognize specific symptom(s) with varying degrees of their airway obstruction, or asthma severity, is poorly understood. Our purpose was to gain a better understanding of how asthma patients during acute episodes, based on their symptom perception, decide when to seek symptom relief. A cross-sectional design was used to study 32, 16 per group, African Americans and Caucasians with a mean age of 34.5 years. All had mild, stable asthma (FEV1 > or = 70%), were non-smokers, atopic, and had not used inhaled or oral steroids for 3 months. Their mean baseline FEV1 was 97.5% predicted; all were controlled with intermittent use of a beta agonist inhaler. All had a bronchoconstrictor challenge using a provocative concentration of methacholine to achieve a 30% fall (PC30) in their FEV1. After achieving a PC30 and before their first dose of a bronchodilator was given, all subjects were asked: "If you felt this way at home would you take your inhaler?" Subjects were blinded to the fact that the yes/no question was asked when their FEV1 was reduced by 30%. In both groups, 44% responded "no" that they would not use their inhaler at that point in time. This finding suggests that those subjects, the 44% who failed to associate a change in their symptoms with increased airflow obstruction, may be at risk for life-threatening episodes.