This presentation has attempted to summarize the role of the adrenal cortex in health and disease. The medical conditions for which cortisone therapy has been employed have been listed, in order to alert the anaesthetist to the possibility of previous treatment with steroids m patients who are suffering or have suffered at any time from these diseases. The various tests for adrenal function are described, as are the treatment of adrenal cortical dysfunction, the complications of treatment, and contra-indications to steroid therapy