Chewing Gum
I don't know what happens when you swallow it, nothing dire, I'm sure. However, I was told that we should not chew gum. When we chew gum, our mouth produces more saliva. When we produce saliva, our old stomach produces more digestive juices, or acid. This causes excess acid in our stomach to build up which can cause ulcers. SO it is best if we forego chewing gum all together.
I was told not to chew gum. It can cause a blockage if the piece of gum is big enough. I had a very bad habit of swallowing my gum and often would do it without thinking about it. Gross, I know. I don't trust myself not to swallow gum, so I just don't bother risking it. I pop a sugar free breath mint in my mouth when I feel like my breath needs freshening.