The internationally accepted term septicaemia is used to describe illnesses in which pathogenic microorganisms are present in the blood. Septicaemia should be defined according to the causative organism, the portal of entry and the underlying disease. In the last 16 years the causative organisms in 788 cases of septicaemia in our hospital were found to be gram-positive cocci in 28.1% gram-negative rods in 37.6%, and other organisms in 24.i%. Infections with Psuedomonas in particular have become more frequent in recent years. The range of causative organisms in septicaemia varies considerably with the patient groups involved. Thus patients with myeloid insufficiency contracted primarily gram-negative septicaemia. As in the past, the pathogens in endocarditis today are primarily streptococci. In hemodialysis staphylococci and gram-negative rods are shown to occur with equal frequency. The most important clinical manifestation of septicaemia is fever with rigor. The poor prognosis in gram-negative septicaemia is mainly due to the onset of septic shock. Skin colonisation is often a typical sign of septicaemia and can also sometimes serve as a diagnostic indication. Hemorrhagic pustules surrounded by a zone of inflammation are typical in septicaemia caused by meningococci or gonococci. Skin eruptions are rare in septicaemia caused by streptococci of staphylococci. Whereas skin eruptions are absent in septicaemia due to enterobacteria, they are very often present in septicaemia caused by Pseudomonas. In bacterial endocarditis a wide variety of skin lesions can occur.