Blood poisoning: The medical term is "septicemia." No matter which of these two terms-blood poisoning or septicemia-you prefer, what is meant is the same thing, namely a "general (systemic) disease that is due to the presence and the persistence of germs (pathogenic microorganisms) or their toxins in the bloodstream." The "germs" can be bacteria (in bacteremia) or any other microscopic agent of infection capable of causing disease in humans. Another term that is very closely related to "blood poisoning" and "septicemia" is "sepsis." "Sepsis" also refers to the presence and persistence of germs or their toxins in the blood but those germs or toxins do not need to be in the blood. They may be in other tissues of the body. Blood poisoning/septicemia and sepsis are often serious. They can sometimes be life threatening diseases calling for urgent and comprehensive care.