The effect of digoxin (0.035 mg/kg b.w., i.v.) on adrenaline-induced hyperglycemia (adrenaline: 50 micrograms/kg b.w., s.c.) and on insulin-induced hypoglycemia (insulin: 0.4 mU/kg b.w., s.c.) was studied in experiments on rabbits. Digoxin intensified the adrenaline-induced hyperglycemia at the 30th and 60th minutes of application. The hyperglycemia in this case subsided more rapidly. Digoxin alone caused on elevation of the blood sugar levels that was most pronounced at the 30th minute of introduction. These elevated levels fell to the initial value by the 180th minute. The blood sugar levels in the rabbits treated with physiological solution rose slightly. This was most noticeable at the 120th minute. Digoxin attenuated the insulin-induced hypoglycemia significantly at the 120th, 150th, and 180th minutes (p < 0.05). We suggest that the increase of the adrenaline-induced hyperglycemia and the attenuation of the insulin-induced hypoglycemia could be linked to the release of catecholamines in the acute stage of the action of Digitalis glycosides.