Fluid therapy is a cornerstone in the treatment of critically ill patients and is one of the most common therapies in intensive care units (ICU). However, excessive fluid therapy has side effects such as tissue oedema and compartment syndromes, which may ultimately worsen outcome. The main objective of the project is to optimize fluid therapy in patients suffering from sepsis/SIRS by investigating how fluids should be given with least amount of oedema and other side effects. The research includes preclinical studies of mechanism of importance for regulation of transcapillary fluid exchange and increases in vascular leak in sepsis as well as studies of pharmacodynamics and pharmacokinetics of resuscitation fluids. The project also includes observational clinical studies and clinical trials in which different treatment strategies to restore normovoleima in patients suffering from SIRS are tested.