More and more patients nowadays who are eligible for rt-PA are already known as demented at admission. A retrospective study conducted in a cohort of patients with dementia who had an ischaemic stroke and were treated by rtPA suggested that there is no increased risk of cerebral bleeding and death as compared with non demented patients. However, pre-existing cognitive impairment is possibly associated with (i) an increased risk of bleeding in patients with cognitive impairment, and (ii) a higher sensitivity to the neurotoxic effect of rt-PA on the brain tissue.