Background Survival rate of patients is associated with the function of the adrenal cortex. Single dose iv injection of etomidate can induce reversible adrenal insufficiency. Thus, more and more attention is focused on the safety of etomidate. Objective To evaluate the effect of etomidate in clinical application on the function of adrenal cortex. Content This paper disscussed the concept and diagnosis of adrenal insufficiency, the effects of etomidate-induced adrenal insufficiency on children, adults, the critically ill and the patients undergoing elective surgeries. Trend Whether etomidate increases mortality in critically ill patients is controversial. The safety of etomidate in the population undergoing elective surgeries remains to be demonstrated by further multi-center and prospective studies.