In most cultures around the world, it is customary to say "God bless you" or some other variation on this when a person sneezes. It is funny that the phase is almost the same in every language: It is "Çok yaşa," meaning "live long" in Turkish while Germans use "Gesundheit," meaning "have a healthy life." But what is it with sneezing?
Why is living a long and healthy life and having God's blessing involved in one of the most human things that we do thousands of times in our lives? Back in the days of the Greeks and Romans, both yawning and sneezing were seen as dangerous bodily reactions because they thought that your soul might discharge from your body while you are doing them.
The ancients believed the human soul could wander around during the day, especially when you are sleeping; hence when a person sneezes, they thought the soul can't find a way to get back in to the body. Hence, saying "Bless you," it was seen as a safeguard for wandering souls.
Another story linked to the common use of this phrase dates back to the sixth century when Europe was at the mercy of the plague and sneezing was the most common symptom of it. To be protected from the plague, Pope Gregory the Great ordered churches around the Catholic world to hold prayers and advised people to respond to anyone sneezing with "God bless you" in order for them to stay safe and alive. In the 21st century, it is well known that a simple sneeze does not let your soul slip away or herald your upcoming death but let's be safe and send God's blessing to all the souls that sneeze around you.