Intensive Care Medicine or critical care medicine is a branch of medicine concerned with the provision of life support or organ support systems in patients who are critically ill who usually also require intensive monitoring.

Patients requiring intensive care usually require support for hemodynamic instability (hypertension/hypotension), airway or respiratory compromise (such as ventilator support), acute renal failure, potentially lethal cardiac dysrhytmias, and frequently the cummulative affects of muliple organ system failure. Patients admitted to the intensive care unit not requiring support for the above are usually admitted for intensive/invasive monitoring, such as the crucial hours after major surgery when deemed too unstable to transfer to a less intensively monitored unit.

Ideally, intensive care is usually only offered to those whose condition is potentially reversible and who have a good chance of surviving with intensive care support. Since the critically ill are close to dying the outcome of this intervention is difficult to predict. Many patients therefore still die in the Intensive Care Unit. A prime requisite for admission to an Intensive Care Unit is that the underlying condition can be overcome. Therefore treatment is merely meant to win time in which the acute affliction can be resolved.