According to Dr. David E. Milov, "swallowing an occasional piece of gum is harmless." However, if you swallow a lot of chewing gum in a short period of time, it may block your intestines, especially if you swallow it with non-digestible stuff like sunflower seeds or coins.
"Who has been swallowing large quantities of chewing gum and coins?" you ask....
Answer: If you ask that question, you are not a parent.