MilitaryIV came to me with the same problem. Drink a #!%+$*+* of 100% Cranberry Juice. It worked for him I don't see why it wouldn't work for you. Mybuddy Lonnie works at a place that does mouth swabs and he said theres a bunch of things that can throw it off. Some examples he gave was eat some garlic,smoke a cigarette, mouthwash RIGHT before you take it (might be kinda hard to do), and chew a piece of strong gum. I haven't tried my buddies method asI've never had a Mouth Swab test. Good luck with it though!