Topical glucocorticoids have always been considered first-line drugs for inflammatory diseases of the skin and bronchial system. Applied systemically, glucocorticoids are used for severe inflammatory and immunological diseases and the inhibition of transplant rejection. Owing to the progress in molecular pharmacology, the knowledge of the mechanism of action has increased during the last years. Besides distinct genomic targets, which are due to the activation of specific cytoplasmatic receptors resulting in the (trans-) activation or (trans-) repression of target genes, there are non-genomic effects on the basis of the interference with membrane-associated receptors as well as with membrane lipids. In fact, various glucocorticoids appear to differ with respect to the relative influence on these targets. Thus, the extended knowledge of glucocorticoid-induced cellular signalling should allow the design and development of even more specifically acting drugs-as it has been obtained with other steroids, e.g. estrogens for osteoporosis prevention. Copyright (C) 2005 S. Karger AG, Basel.