1. Subcutaneous injections of l-adrenaline caused adrenal ascorbic acid depletion in normal rats. 2. Previous treatment of rats with deoxycorticosterone acetate ('DCA') prevented the fall in adrenal ascorbic acid concentration caused by the administration of adrenaline. A quantitative relationship existed between the dose of adrenaline injected and the dose of DCA required to prevent its effect. 3. The application of stress stimuli resulted in a rapid fall in the ascorbic acid concentration in the demedullated adrenal glands of rats. Maximal effects were obtained as soon after the performance of the operations as in rats with normal adrenal glands. 4. Pre-treatment of adrenal-demedullated rats with DCA diminished the fall in adrenal ascorbic acid concentration caused by stress. The doses of DCA required to prevent completely the adrenal ascorbic acid depletion due to stress were of the same order as those required to produce the same effect in normal animals. 5. The possible significance of these findings is discussed.