God bless you

Bless you is a common English expression used to wish a person well after sneezing.

Origins

One traditional explanation for the custom is that it began literally as a blessing. Pope Gregory I the Great (AD 540-604) ascended to the Papacy just in time for the start of the bubonic plague in AD 590 (his successor succumbed to it). To combat the plague, Gregory ordered litanies, processions, and unceasing prayer for God's blessing. When someone sneezed (seen as the initial onset of the plague), they were immediately blessed ("God bless you!") in the hope that they would not actually develop the disease.

Superstition

Other explanations are based on superstitions and urban legends about sneezing and what a sneeze entails. Some well known superstitions that may have contributed to bringing "bless you" into common use are:

• The belief that the heart stops when you sneeze, and the phrase "bless you" is meant to ensure the return of life or to encourage your heart to continue beating. (Of course, the heart beats because of electrical pulses that are not affected by normal functions like sneezing.)
• A sneeze is the expulsion of some sort of evil, and the phrase is meant to ward off the evil's re-entry. Due to this some people believe that it is unlucky to say thank you, as this allows the evil to return. In Ireland if you say 'Thank you' a leprechaun dies. IN other countries a fairy dies.
• Your soul can be thrown from your body when you sneeze, and saying "bless you" prevents your soul from being stolen by Satan or some evil spirit. Thus, "bless you" or "God bless you" is used as a sort of shield against evil.
• A sneeze is good luck and saying "bless you" is no more than recognition of the sneezer's luckiness.

Alternatively, it may be possible that the phrase began simply as a response for an event that wasn't well understood at the time.

Another urban legend states that you cannot open your eyes while you sneeze, or if you manage to your eyes will pop out. During a sneeze the impulses travel through your face causing your eyelids to blink, this response is entirely automatic.

In many English-speaking countries, the German equivalent, gesundheit (which means "good health"), is used after sneezing or coughing.

Alternative intent

One other usage of the phrase "Bless you" in response to a sneeze is to bless or thank a person who sneezes but covers his or her mouth and nose with a tissue, handerkerchief, sleeve, or even a hand (hopefully then washing the hands before touching shared items) as an act of concern and courtesy to others, in order to avoid spreading the germs expelled so as not to sicken other people. Presumably, a person who fails to demonstrate such concern and courtesy by not covering the mouth and nose during a sneeze would not be blessed or thanked.

References

1. Dr.Tom Wilson of Washington University School of Medicine. 1998. [1]
2. Opie, Iona, and Moira Tatum. A Dictionary of Superstitions. Oxford University Press; Oxford, 1992. ISBN 0-19-282916-5
3. Snopes Urban Legends - Bless You!