Question: what makes people sneeze?

Ciarán O'Brien answered on 21 Nov 2014:

Sneezing is kind of an allergic reaction.

Your body takes care of a lot of its own day to day running. Your brain keeps the heart beating and your lungs breathing, and takes care of digesting food after you swallow it. It also takes care of dealing with irritation. Often you’re half way towards scratching an itch before you realise you even had one. If your stomach feels like it’s got something bad in it, your brain makes you vomit to get rid of it.

And if there’s something up your nose that shouldn’t be there, your brain will cause you to sneeze and get it out. Anything that gets caught in your nose can make you sneeze. Dust, pollen (reactions are much worse if you’re allergic to these things), water, your own snot, or even just a nose hair tickling the inside of your nose.

One time a couple of years ago, I was eating a delicious spicy pizza while watching something funny on TV. When I laughed I choked a little bit, and one of the chilli peppers on the pizza went up my nasal passage from the back. I started sneezing like crazy and eventually I sneezed the chilli pepper all the way from the back of my throat, out my nose! It burned all the way out my nose, it was horrible 🙁