Four commercially available topical preparations of cortisol, Alphaderm, Calmurid HC, Efcortelan and Topisone, had trace quantities of tritiated cortisol added to them. The resultant radiolabelled creams were applied to the dorsum of the pig and the penetration of the steroid was assessed. Alphaderm was shown to deliver approximately 16.0 times more cortisol to the skin than Topisone, approximately 8.0 times more than Efcortelan and approximately 3.0 times more than Calmurid HC.