Cardiac surgery with cardiopulmonary bypass (CPB) is associated with activation of the complement system, platelets, neutrophils, monocytes, and macrophages which may lead to systemic inflammatory response syndrome in several cases. Despite modification of surgical techniques, biocompatibility of the bypass circuit and intensive care procedures after operation, CPB is still associated with post-operative morbidity including reduced cardiac function, capillary leak or multi-organ dysfunction. Corticosteroids are known for their anti-inflammatory effects and therefore, they are beneficial in selected trauma or septic patients. Prophylaxis with corticosteroids in cardiac surgery has been used since decades. The studies for methylprednisolone and hydrocortisone, the most commonly used corticosteroids, show conflicting results. For hydrocortisone, which is the mainstream of corticosteroid treatment in septic patients, the number of studies is low, but will increase in the next years. This article reviews the data concerning its use in patients undergoing cardiac surgery, its contraindications, adverse effects, risks, and benefits.