Severe stroke is an emergency and requires rapid neurological assessment and diagnosis. CT scan is the first diagnostic step with the aim of finding out the extent, localization and possible pathophysiology of ischaemia in order to direct specific diagnostic and therapeutic options. An intracranial haemorrhage must be excluded. Early CT signs, including the size of the hypodensity and brain swelling, are important prognostic markers. Extracranial and transcranial Doppler sonography are valid for primary assessment of vascular pathophysiology and haemodynamics in most cases. Cerebral angiography should be performed if acute occlusion of the basilar artery or middle cerebral artery trunk is suspected and intra-arterial thrombolysis is a potential therapy. Intravenous thrombolyis has been proven to be effective in improving outcome in severe stroke; it is safe if the exclusion criteria are strictly applied. Prevention of secondary complications of stroke include general medical treatment with control of blood pressure, infections and cardiac and respiratory function, anti-coagulation. anti-oedematous treatment and surgical decompressive therapy for cerebellar and MCA space-occupying infarcts. Monitoring in the ICU is recommended. The medical therapy of intracerebral haemorrhage consists of control of ventilation and blood pressure, seizure prevention and anti-oedema treatment. Treatment of secondary ICH due to anti-coagulation or thrombolysis consists of administration of specific antidotes and the correction of the coagulopathy. Ventricular drainage should be performed when there is marked ventricular dilatation due to obstruction or blood in the ventricles. Most patients with cerebellar haemorrhage of more than 3 cm in diameter should undergo surgery to avoid brain-stem compression and hydrocephalus. In younger patients, non-dominant hemisphere putaminal and lobar haemorrhages with lateral displacement of midline structures and extensive oedema should be evacuated if the patient's level of consciousness deteriorates rapidly, or if the elevation of ICP cannot be controlled pharmacologically, and herniation is incipient. New techniques such as stereotactic and endoscopic evacuation still need to be tested prospectively. Patient selection for surgery should be cautious considering age, clinical status and possible contraindications such as cerebral amyloid angiopathy and coagulation disorders. Stroke therapy is rapidly becoming a focus of research and major changes in diagnostic and therapeutic options can therefore be expected.