Some 3 million children undergo anesthesia and surgery in the United States every year; 40% to 60% of these children develop significant behavioral stress prior to surgery. Multiple interventions have been suggested to treat the preoperative behavioral stress responses in children. There is a trend toward reducing both behavioral and pharmacological preoperative interventions aimed at children, perhaps because though there is a consensus that preoperative interventions can be useful, almost no outcome studies have evaluated the effects of these interventions on measurable, clinically "important" postoperative outcomes. More research is needed in this area.