Why do we say bless you when someone sneezes?

The most commonly repeated origin story attributes the custom to Pope Gregory the Great, who is said to have ordered blessings for sneezers during a plague epidemic in Rome around 590 AD, when sneezing was an early symptom. The account is plausible but poorly documented, and historians treat it as tradition rather than established fact. Similar customs appear independently across many cultures and long predate Christianity, with Greek and Roman writers noting responses to sneezes, which suggests the impulse to say something is older and more universal than any single origin.

The folk explanations attached to the custom are more entertaining than accurate. The heart does not stop when you sneeze, though the sudden pressure change can briefly alter its rhythm, which is probably where the belief came from. The soul does not escape, and the idea that a sneeze expels evil spirits or invites them in belongs to a broad family of protective superstitions. What is true is that sneezing was historically a genuine omen of illness in eras without antibiotics, so acknowledging it made social sense. Other languages preserve different responses with the same protective instinct, German gesundheit meaning health, Spanish salud, and various expressions across cultures wishing long life, which is why the English blessing is one local variant of a very widespread reflex.