Septicaemia is a serious condition: infection has left one place in the body and is travelling through the blood. Bacteria, or the poisons they make, are in the bloodstream. Everyday English often calls this blood poisoning. The British spelling keeps ae in the middle (septicaemia); American English writes septicemia. It is a hospital word. On the news you will also hear sepsis. Doctors today often use sepsis as the big name for the dangerous whole-body reaction, and septicaemia for infection in the blood; ordinary readers, and many headlines, treat them as the same frightening thing. You do not use this word for a mild cold, or for a small infected cut that stays in one spot.

敗血症（感染入血）。對照 sepsis 那一條：台灣多半兩個都叫敗血症；口語也說「血液中毒」，比較不像病名。