In short, no-one knows. A common story is that during the time of the Bubonic Plague (of which sneezing was an early symptom) people would say "bless you" in case the sneezer had the plague - the practise having started in 590 by Pope Gregory I.
However, it's known that people have said "Bless-you" after a sneeze since at least 77AD, so the plague explanation seems unlikely.
Bless you.
I do
You just say bless you.
In Portuguese, you can say "saúde" which means health or "Deus te abençoe" which means God bless you in response to a sneeze.
they say bless you because when you sneeze your heart stops's there thanking god that you did not die
When someone sneezes the common response is "bless you".
Because everytime u sneeze u lose a day of life\( ^.^ )/
selena gomez always says bless you from SELENA<3
people used to think that if you sneezed you sneezed out your soul and they say bless you so the devil wont get it.
God bless you = Gott segne dich (God) bless you! (after a sneeze) = Gesundheit!
Que dieu te bénisse / vous bénisse
Legend tells that when you sneeze, the soul leaves the body with your breath. At that point, it is available for possession by an evil spirit. Saying "Bless you" prevents the evil spirit from entering the body when you catch your breath.Apparently, when you sneeze, your soul escapes. So if someone says bless you, the devil can't catch it.