SummaryIt is generally held that, besides changes in insulin activity, clinical doses of cortisone have no definite effect on carbohydrate metabolism of normal subjects.By mathematical analysis of intravenous glucose tolerance tests, it is possible to calculate a glucose assimilation coefficient and to detect thereby changes in carbohydrate metabolism which escape other methods of investigation.The alterations induced by cortisone administration arc important and depend on duration of treatment. In the early stages, glucose assimilation is depressed. After 3 weeks, it returns to normal values. Later, in spite of continued treatment, the glucose assimilation coefficient rises above the initial figures.