If you swallow your chewing gum, it will take seven years to digest. Or not. Scientific American gets to the bottom of this sticky situation. The bottom line is that swallowed gum isn't easily digested but it does make it out the other end, albeit slower than other edibles. Still, it's apparently a better idea to spit than swallo. From the article:
As Milov and his colleagues wrote in Pediatrics in 1998, chronic gum swallowing–or swallowing gum in conjunction with other indigestibles–can spell trouble. The team's report describes three children suffering from gum-based gastrointestinal blockages, two of whom received gum as positive reinforcement for good behavior and regularly disposed of the treat by swallowing it. In both cases the children became constipated, as the gum snowballed into a substantial "taffylike" mass that required extraction. In the third patient, a girl just a year and a half old, four coins were found lodged in the esophagus, fused into a single blob by a wad of chewing gum.
"I've had another case that was really interesting," Milov adds, "and that was somebody who swallowed sunflower seeds–[and] also, the shells." Upon examining the patient's lower digestive tract, Milov found "all these very prickly seeds that were congealed around gum," forming a body that he describes as "like a porcupine."
