Abstract The excretion of urinary glucocorticoids was studied in a group of fifty-eight patients during active asthma. It was shown that persistence of symptoms is not associated with a rise in the level of glucocorticoid excretion in the urine. Spontaneous recovery from asthma and recovery induced by nonspecific therapy, however, are associated with a rise in urinary corticoid excretion. The results suggest that the asthmatic patient may excrete smaller quantities of urinary corticoids than do normal subjects and that the persistence of symptoms may be due in part to an inability of the pituitary or adrenal to augment the output of corticoids or to respond to the stimulus of asthma. The results in two cases of urticaria and nine of atopic dermatitis do not differ significantly from those found in normal subjects, and in this respect they differ from the asthmatic patients.