Hyperosmolar non-ketotic coma is a relatively uncommon but important medical emergency. It is associated with a high mortality, which has changed little over the past twenty years. Approximately half of all patients give no prior history of diabetes and since patients often present with neurological abnormalities, resembling a cerebrovascular accident, the diagnosis can sometimes be delayed or missed. Therefore every patient presenting to hospital with a state of clouded consciousness or objective signs of neurological abnormality, should have a blood glucose estimation performed at an early stage. It has been suggested that a regimen of less aggressive early fluid replacement, with more attention being directed to the associated or underlying problems, may be beneficial to the patient. Claims that the continuing high mortality in non-ketotic coma can be improved by such measures await confirmation.