Emergence agitation is a clinical condition in which the child experiences a variety of behavioural disturbances including crying, thrashing, and disorientation during early awakening from anaesthesia. Emergence agitation is a common challenge in children with a reported incidence of approximately 25% ranging from 10 to 80 %. Clonidine is often used off-label in paediatric anaesthesia e.g. sedation in the intensive care unit, prevention of withdrawal symptoms after long-term sedation, as premedication before induction of anaesthesia or as treatment/prevention of emergence agitation. The study is designed as a randomised, placebo-controlled clinical trial evaluating efficacy and safety of a single dose of intraoperative clonidine in children 3-12 months, including pharmacokinetics.