It is true that the body is unable to digest gum. This is because gum contains gum resin. There are materials in gum that the body can use, such as sugar or artificial sweeteners, but it cannot digest the resin portion. So, what happens to this gum resin? It simply moves through the digestive tract until it can be passed in the feces. Swallowing a lot of gum over a long period of time can cause problems though. Sometimes this gum can build up in the body and cause blockages in the digestive tract which can be dangerous.