The fine border between the optimal dose of steroids and the collateral effects can not be overlooked given the results of some recent studies (relative to patients with chronic inflammatory bowel disease or children with acute lymphoblastic leukemia subject to prolonged cycles of steroid therapy) based on the pharmacogenetic evaluation of the diverse individual responses to steroids. Clinical data supports the concept that the collateral effects of steroids are not exclusively dose related, but can depend on constitutional hypersensitivity or resistance, at times specific for a particular corticosteroid.