σῆψις

Sēpsis in Greek means rotting, putrefaction, from sēpein (to make rotten, to cause decay). Hippocrates used the word around 400 BCE to describe the dangerous, sometimes fatal deterioration that followed wound infections. The word was grimly literal — wounds that became septic rotted visibly, with necrotic tissue, foul odor, and systemic collapse. Sepsis was death by decomposition while still alive.

Ignaz Semmelweis discovered in 1847 that hand-washing with chlorinated lime solution dramatically reduced maternal death from 'childbed fever' (puerperal sepsis) — from 18% to under 2%. His colleagues rejected his findings. Semmelweis was dismissed, ridiculed, and eventually committed to a mental institution, where he died in 1865. The bacterial cause of sepsis was not proven until Pasteur and Koch's work in the 1870s and 1880s. Semmelweis was right twenty years too early.

Modern medicine defines sepsis as a life-threatening organ dysfunction caused by a dysregulated host response to infection. The definition was updated in 2016 (Sepsis-3). The key insight is that sepsis is not the infection itself but the body's overreaction to it — the immune system's inflammatory response becomes so extreme that it damages the body's own organs. The defense becomes the disease.

Sepsis kills an estimated 11 million people worldwide per year — more than cancer. It is the leading cause of death in hospitals. Early recognition and treatment (antibiotics, fluid resuscitation, vasopressors) dramatically improve survival, but many cases are diagnosed too late. The Greek word for rotting now names the condition that modern medicine struggles most to catch in time.