This paper aims to provide an update on the main aspects of sepsis, a very relevant health care issue. A number of hypotheses have been proposed to explain its origin, involving interactions between microorganisms and the innate immune system, inflammation/immune mediation and the coagulation system. The clinical features of sepsis are variable and depend on the primary site of infection. The identification of early signs and symptoms is crucial for starting therapeutic measures fundamentally based on volume resuscitation, antibiotic therapy, use of steroids, anticoagulant therapy, biologic viability maintenance interventions and nutritional support.