I feel for you, really. It is SO annoying and it makes it impossible to concentrate. Even worse at work when you have to get work done right next to her! I once had a coworker sit next to me and eat her lunch really loudly at her desk. I always had to walk around the office, go to the bathroom, get a glass of water, etc until she was finished. Can you mention something to the management about creating a no-gum policy in the office? It really should be in place to begin with. Good luck! Let us know what happens.