While growing up, you probably heard more than a few random ‘facts’ from grown-ups. Things like ‘if you eat watermelon seeds, a watermelon will grow in your stomach’ or ‘the moon is made of cheese’. One such tale involves chewing gum, and more specifically, what would happen if you swallowed it by accident. As children, we were told that it takes at least 7 years to digest.

What is chewing gum made out of?

Chewing gum is made up of about 75 to 85% sweeteners, flavoring, and starches – all of which are digestible. The remaining 15 to 25% consists of synthetic polymers like butyl rubber. In chemistry labs, butyl rubber is used to seal flasks containing fluids like hydrochloric acid, which is 30 times stronger than stomach acid.

So, what happens to swallowed gum?

Since butyl rubber is stronger, your stomach acid won’t be able to break down the chewing gum, but the gum will eventually move through your digestive system and come out at the other end.

Contrary to what many folks may think, when you consume food, it doesn’t just sit in the stomach doing nothing. Your entire digestive system functions like a conveyer belt. Food moves through the intestines via the process of peristalsis; a certain part of the food is broken down (i.e. digested) and absorbed through the intestines, while the undigestible part is passed out in the loo. So, when you accidentally ingest chewing gum, it usually follows the same route as the undigested food: out to the loo.

In summary

Chewing gum won’t take seven years to digest, as we were led to believe when we were young. The bulk of the gum will digest as normal, while the indigestible part (i.e. resin) will move right through the digestive tract and eventually be eliminated. There have been reports, however, of children who had blocked intestines due to swallowing a large amount of chewing gum. And unfortunately, this blockage could only be removed with surgery. Occasionally swallowing a small piece of gum is likely harmless, but it’s best not to make a habit of it!