In addition to the gum base, chewing gum contains sweeteners, flavorings, and softeners. Softeners are ingredients such as glycerin or vegetable oil that are used to blend the other ingredients and help prevent the gum from becoming hard or stiff.
Neither natural nor synthetic latex are readily degraded by the digestive system. However, if you swallow your gum it will almost certainly be excreted, usually in pretty much the same condition as when you swallowed it. However, frequent gum swallowing may contribute to the formation of a bezoar or enterolith, which is a sort of intestinal stone.