Laryngoscopy and endotracheal intubation is a potent sympathetic stimulus in adults. Neonates are frequently intubated, but few data exist on the cerebral effects of this intervention. The cardiovascular and intracranial effects of laryngoscopy and endotracheal intubation were studied in 17 hypercarbic neonatal piglets. The mean arterial pressure in the study group (11 piglets) increased significantly within 2 minutes of the stimulus, and remained elevated for almost 14 minutes. The intubated animals showed significantly more haemorrhage in the basal area of the brain than the 6 control animals. The distribution suggests bleeding in the choroid plexus of the 4th ventricle. The significance of such bleeds is not immediately apparent, since none of the animals was grossly neurologically affected by the intervention. However, subtle long-term neurological deficits cannot be excluded and this aspect requires further study. Laryngoscopy and endotracheal intubation may cause non-lethal haemorrhage in the choroid plexus and central canal of the hindbrain in hypercarbic, neonatal piglets.