Abstract: Percutaneous absorption of hydrocortisone was measured by a four hour absorption test in 16 children during and after the acute phase of dermatitis. In the acute phase, after the application of 1% hydrocortisone cream the increment in plasma cortisol ranged from 47 to 961 nmol per liter (median 248 nmol/L). After the acute phase the increment was significantly (P < 0.01< lower: range 18 to 241 nmol per liter (median 95 nmol/L). In addition to local effect, topical hydrocortisone therapy of childhood dermatitis is accompanied by a systemic effect that may be pronounced in the acute phase of disease. Convalescience is connected with a diminished systemic effect due to the restoration of the skin barrier to hydrocortisone.