Low levels of serum glucose have been observed in atopic individuals after a subcutaneous injection of epinephrine. This less than normal hyperglycemia could be evidence of partial beta-adrenergic blockade in atopy. We compared the basal values of glucose with those obtained after 30 and 60 minutes of a subcutaneous injection of epinephrine 1/1000 (0.006 ml/kg; maximum of 0.3 ml) in normal and atopic asthmatic children (mild, moderate, and severe). The glucose-oxidase method was used for the determination of glucose levels in peripheral blood. Glucose serum levels in normal children were significantly higher at 30 and 60 minutes compared with basal values. In patients with mild and moderate asthma, significantly higher values were observed only at 30 minutes. In severe asthmatics, the glucose levels at 30 minutes were not different from the basal values, but higher than those observed at 60 minutes. Comparison among the four groups showed significant differences between the nonatopic normal children and the severe asthmatic children at 30 and 60 minutes. The moderate asthmatic children showed significantly lower levels when compared with nonatopic normal children at 30 minutes.