in most cases swallowed gum digests as little slower as normal food, but it digests

One old wives' tale says that swallowed gum will remain in a person's stomach for up to seven years, as it is not digestable. According to several medical opinions, there seems to be little truth behind the tale. In most cases, swallowed gum will pass through the system as fast as any other food, but can be a little slower.^[6] There have been a few cases where swallowing gum has required medical attention, but these cases are more or less related to chronic gum swallowers. One young boy swallowed several pieces each day and had to be hospitalized,^[7] and another little girl required medical attention when she swallowed her gum and four coins, which got stuck together in her oesophagus.^[8] As long as the mass of gum is small enough to pass out of the stomach, it is unlikely they will experience any problems.

http://en.wikipedia.org/wiki/Chewing_gum