Patients with systemic disorders are often seen in dental practice. If not adequately evaluated, the existence of such alterations may lead to undesirable clinical situations. This is the case of patients with adrenocortical insufficiency. The causes underlying such insufficiency require a distinction between primary adrenal insufficiency or Addison's disease, involving an intrinsic alteration of the adrenal gland cortex, and secondary adrenal failure attributable to hypophyseal or hypothalamic pathology. Another frequent situation involves patients subjected to high-dose steroid therapy -- which induces a reduction in ACTH (adrenocorticotropic hormone) secretion with secondary atrophy of the adrenal cortex. In this context, sudden interruption of corticoid therapy gives rise to acute adrenocortical insufficiency, particularly if the patient is subjected to some form of stress. Corticotherapy is provided in many disorders such as autoimmune connective tissue diseases, different types of cancer, blood dyscrasias and transplant patients, among others. This makes it likely for dentists to occasionally see patients who are receiving, or have received, corticoid treatment. Some of these patients may be unable to tolerate the stress of dental treatment, thus giving rise to the risk of acute adrenal cortical failure. The present study addresses the prevention of these unpleasant and hazardous situations, with a review of the different corticoid replacement therapies applicable in dental practice.