One of the groups of patients which may require the greatest flexibility of approach is those with autistic spectrum disorder (ASD). ASD is a lifelong developmental disability, affecting four times as many males than females, which affects how a person communicates with, and relates to, other people and the world around them. Challenging behaviors may be triggered by the unfamiliar perioperative environment and may make anesthesia related procedures difficult or impossible. Children with more severe ASD may exhibit verbal or physical aggression, antisocial or disruptive behavior, temper tantrums, screaming, panic attacks, and self-injurious behavior, and may have aberrant responses to sensory stimuli. Although anaesthesia and sedation do not present a problem for most children with ASD, unpredictable regression in skills and behaviour is noted in a small number of patients after general anaesthesia. A 10-year-old child, 53 kg, with autism under treatment, came for a dental abscess and related dental work under general anaesthesia. The pediatric neurological assessment indicated hyperactivity and lack of cooperation. Post-operatively, during resuscitation, the child showed agitation and an attempt to withdraw oxygen, with the physical presence of his family environment.