After an intervention that involves the surgical removal of large quantities of liver – explains Dr. Roberto Ceriani, Head of the Section of the Hepatological Day Hospital and interventional hepatology at Humanitas. The liver begins to regenerate without ever losing its functions of synthesis, detoxification and metabolism of substances. The alterations felt by the organ following a surgical procedure but also after liver infection, activate and deactivate numerous mechanisms, some of which are still not completely clear, that guide the regeneration process. Growth factors, immune system cells such as leukocytes, macrophages, eosinophils and lymphocytes, platelets, liver starry cells and bile epithelial cells are activated in the liver, thus activating quiescent cells, i.e. not yet differentiated cells and therefore without specific functions, which have a high capacity for regeneration and transformation. These processes begin immediately after hepatic infection or surgery, but the main regeneration activity of the liver takes place on the third day after injury, while complete recovery occurs after 5-7 days. Although the regeneration mechanism is not yet fully clear, however, the fact that the liver is a continuously sprayed organ with blood rich in nutrients as well as toxins from the intestine, may be the reason why the liver has this unique regenerative capacity.