Despite their antiinflammatory and antiallergic properties, corticosteroids can nevertheless cause adverse allergic reactions. This is currently accepted for local corticosteroids and there have also been about a hundred reports of variable pertinence concerning hypersensitivity reactions to systemic corticosteroids. Based on three cases of immediate hypersensitivity reactions after taking methylprednisolone, we propose a critical review of the literature, focusing particularly on methylprednisolone-induced reactions. The means of investigation currently available in drug-induced hypersensitivity reactions are also discussed.