Multiple organ failure (MOF) can affect any organ and systems not thought of as organs such as endocrine, immune, haematological and therefore it has also been called multiple systems organ failure (MSOF). Patients with multiple organ dysfunction syndrome (MODS) make up 10-15% of the intensive care unit population and typically have two to three organ system dysfunctions at time of diagnosis; hypoxia, shock and oliguria are the most common combination. The different components of MODS are: respiratory system, renal system, gastrointestinal system, hepatic system, neurological system, haematology, immunology, and endocrinology and metabolism. No single treatment for MODS can be recommended because it is a maladaptive response to acute severe inflammation and therefore a complication to be prevented rather than a syndrome to treat. Patients with impaired host defence mechanisms are at greatly increased risks of developing sepsis and MODS. Sepsis requires urgent antibiotics and source control with or without surgery.