An intensive care unit (ICU) is a special department of a hospital or health care facility that provides intensive treatment medicine. Intensive care units cater to patients with severe and life-threatening illnesses and injuries, which require constant, close monitoring and support from specialist equipment and medications in order to ensure normal bodily functions.

They are staffed by highly trained doctors and nurses who specialize in caring for critically ill patients. ICUs are also distinguished from normal hospital wards by a higher staff-to-patient ratio and access to advanced medical resources and equipment that is not routinely available elsewhere. Common conditions that are treated within ICUs include acute (or adult) respiratory distress syndrome (ARDS), trauma, multiple organ failure and sepsis.