A 6-year-old boy presented for surgery for phimosis. The anaesthetic technique included intravenous induction with thiopentone and neuromuscular blockade with cisatracurium. Severe persistent bronchospasm and central cyanosis followed the administration of these drugs. A continuous i.v. infusion of epinephrine at 0.2 microg. kg(-1) x min(-1) was necessary to break the severe refractory bronchial hyperresponsiveness. There was no previous exposure to anaesthetic drugs and no definite family history of allergy. Through increased serum eosinophil cationic protein, tryptase and histamine levels and IgE levels specific to cisatracurium, we demonstrated an IgE-mediated anaphylactic reaction to cisatracurium in the child's first exposure to this new neuromuscular blocking agent. Anaphylactic reactions to new anaesthetic drugs may be challenging to recognize and treat during general anaesthesia in children. The pathogenesis, diagnosis and management of life threatening persistent allergic reactions to intravenous anaesthetics are discussed.