Alpha2-agonists have been extensively used and studied in anaesthesia and intensive care medicine. A list of benefits includes anxiolysis, blood pressure stabilization, analgesia, anaesthetic sparing effects and sedation without respiratory depression or significant cognitive impairment. Fear of inadvertent hypotension, bradycardia or post-operative sedation, and the variability of the haemodynamic response to different doses or rates of administration, have meant that universal acceptance in clinical practice has not yet been seen. Recently, the actions of these agents on the alpha2-adrenoreceptor and the imidazoline receptor have been more accurately identified, helping to explain the differences between the actions of various agents. The two readily available agents, clonidine and dexmedetomidine have already been used in many different anaesthetic situations, for a wide variety of surgical procedures. We believe that both of these alpha2-agonists are useful adjuncts for the management of the neurosurgical patient during surgery, and in the intensive care unit.