Background/PurposeThis prospective, randomized, and observer-blinded study was performed to evaluate the effects of oral chloral hydrate on perioperative psychological and behavioral phenomena in children. MethodsIn total, 100 boys (age, 1-5 years) scheduled for day-case unilateral orchiopexy were randomly allocated into 2 groups and orally administered either 40 mg/kg of chloral hydrate (CH group) or placebo (control group) 30 minutes before surgery, followed by assessment of anxiety, induction compliance, emergence delirium, postoperative pain, and maladaptive behavioral changes. ResultsAnxiety scores were significantly lower in the CH group compared with the control group (45.7 vs 28.8). The induction compliance of the CH group was better than that of the control group (3.2 vs 4.8). Postoperative sedation was more frequent (62.7% vs 20.4%); however, the incidence of vomiting was lower (2.0% vs 14.3%) in the CH group than in the control group. Postoperative emergence delirium and maladaptive behavior changes were similar between the 2 groups. ConclusionDecreasing preoperative anxiety with oral chloral hydrate improves induction compliance and reduces postoperative pain intensity without delaying recovery in young boys. However, chloral hydrate had little impact on emergence delirium and postoperative maladaptive behavior.